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Gonna Build Me a Rotovap Update 2: Vacu-Forming Nightmare

August 22nd, 2009 · rotovap

posted by Dave Arnold

As readers of this blog might know, I’m building my own rotovap. See here and here. If you don’t know from rotovaps, see here.

Here is the latest:

The new rotovap is designed without a rotating vacuum seal—one of the crappiest parts of the laboratory system. The liquid to be distilled will be sealed in a heated inclined stainless steel semi-cylinder with a semi-cylindrical PETG lid (PETG is an easy to work with, clear, alcohol resistant plastic). A polycarbonate cylinder inside will be rotated magnetically to provide the agitation and surface area needed for rotary evaporation. Here is my new rotovap base, and what it replaces:

On top: new rotovap base; on bottom: what it replaces.

On top: new rotovap base; on bottom: what it replaces.

The lid isn’t perfect, but here’s how I made it:

I’ve wanted to do vacuum forming since I was a kid; this was my first real foray. Vacuum forming is a simple technique: A sheet of hot, flexible thermoplastic is held in a rigid frame and forced to conform to a mold using the suction from a vacuum. Well made vacuum-formed products have good surface finish and structural qualities and can take complex shapes without the hassles of casting or machining. I knew the new rotovap lid had to be plastic so it would be both transparent and super strong;  I knew that it should be curved to better withstand the forces of vacuum distillation. Vacuum forming seemed like the right process to get the job done. I had kinda vacuum-formed for my Mokume-Gane fish slicing technique, so I felt fairly confident in my abilities. Ha.

I started by reading some DIY web tutorials on vacuum forming like this one on the Instructables site. Making the form was the first step. I used blue Styrofoam because it is cheap, easy to cut, and it came recommended. I built a hot-wire foam cutter to help me:

Wire foam-cutter kludged together from a hack-saw, dimmer, dowels, and an old transformer. Make sure you tape up the handle or you'll get zapped!

Wire foam-cutter kludged together from a hack-saw, dimmer, dowels, and an old transformer. Make sure you tape up the handle or you'll get zapped!

A hot-wire foam cutter is one of a long list of tools I’ve always wanted but can’t justify buying. The one I needed for this project costs $200 (too much) so I turned to the tech team’s scrap closet. I had some nichrome wire for the heating element (too thick really, but would do), an extension cord, an old transformer (couldn’t really handle the current I needed but would work long enough), a dimmer, a hacksaw, a hose clamp, a wooden dowel, some screws, and electrical tape. You can see how I rigged it in the picture above. Miraculously, it works. Turn on the dimmer till the wire starts singing, and cut away. Cardboard cutting guides (see the black half circle in the photo) help a lot. This thing would actually be a really nice tool if I invested 3 dollars in the right gauge of nichrome wire and found a beefier transformer.

After wire cutting, sanding, and puttying here is my form:

Ready to vacuum form --or so I thought! The exposed Styrofoam was a problem as was the surface quality as was the lack of release agent.

Ready to vacuum form --or so I thought! The exposed Styrofoam was a problem as was the surface quality as was the lack of release agent.

I would later learn that I made some major mistakes right out of the gate.  Turns out the PETG would pick up a lot of surface detail, and my mold wasn’t smooth enough. Styrofoam compresses a bit so I should have spackled over the whole thing with bondo to provide more rigidity. And a release agent to prevent the PETG from gluing to the form would have been a nice addition. But I’m getting ahead of myself…

The next step was building the forming table, typically just a flat surface with some perforation and a vacuum hooked up to it. But I didn’t want to use a flat table because the PETG would have to form over the whole base of the rotovap if I did. I built a forming box out of MDF instead, so the base of ‘vap would be covered. Next, I needed to connect the box to a vacuum source. Most people use shop vacs for suction.  I don’t have a shop vac, so I opted to use our Minipack vacuum sealer; it can suck more than enough cfm’s and provides a very high quality vacuum. One problem: The vacuum inlet of the Minipack is metric. Now… I’ve come to grips with cooking in Celsius. I’ve learned to accept the millimeter and the gram. But metric pipe fittings are the devil’s own work. They are weird and impossible to find in the US. I hate them. Instead of endlessly searching for the right fitting, I just molded some silicone onto a hose barb and jammed it into the vacuum inlet as an adapter. The last step was building a rigid frame to hold the plastic while it was being formed. This step turned out to be more critical than I thought. I used cut-up aluminum rulers and spring clamps for my frame, instead of the universally recommended aluminum window-screen extrusions (see the instructables site) because the local hardware stores didn’t have them. The PETG I was using was 1/4 inch, which is pretty damn thick. I should have used a tough frame. In retrospect, I doubt even the window screen stuff would have held up. But what I had was laughable.

I loaded the frame with plastic wrap, turned on the vacuum, and did a test pull. It was perfect. It sealed beautifully. Awesome. We clamped up the PETG, threw it in a 350°F convection oven, and waited for the plastic to slump, an indication that it’s soft enough to mold.

We turned on the vacuum and pulled the PETG out of the oven. It was hard to move that plastic around without getting burned. In fact, I burned myself pretty badly. Making matters worse, the aforementioned frame just disintegrated as my interns and I started to push down the PETG in our attempt to mold. The plastic was too thick and stiff and the frame too weak. A lot more force was required than I thought. A lot more. Burned and furious, I threw the PETG onto a sheet tray and back in the oven to soften more while I  held both my wrists in ice water.

After another 5 minutes in the oven, we pulled the PETG out and quickly loosened it from the sheet tray with an offset spatula. The sheet looked pretty bad. It was mangled on the edges. Little bubbles had appeared where we had put grease to help the frame form a seal (hint: don’t use grease). I pretended this was all OK and pressed on. We tried to make the PETG seal over the mold by hand. Let’s just say it wasn’t working. The only thing redder than my burnt wrists was my screaming face. Then I had an idea: plastic wrap. I yelled for plastic wrap and the interns started covering our whole contraption with it. As the first layer went down, we could tell it was working. The PETG started to mold! Almost immediately we heard a suck and pop noise as the plastic wrap blew out under the suction. In unison, we all cried, “more plastic!” I have never witnessed such a feat of Spiderman-like wrapping. As fast as hands could move layer after layer of plastic wrap went over the mold. It was holding! Suddenly, the vacuum machine turned off at the end of its cycle (another eventuality I should have foreseen) and we scrambled to start it again.

Vacuum forming nightmare. You can see the broken frame in the background and us rushing around trying to seal the thing with plastic wrap.

Vacuum forming nightmare. You can see the broken frame in the background and us rushing around trying to seal the thing with plastic wrap.

After three vacuum cycles, as someone was placing ice packs (also made of plastic wrap) on the mold to cool it off, another mishap: My hastily made silicone adapter got sucked into our vacuum sealer with a quick shluuump noise, quickly followed by some choice expletives from me.  True, the worst was over, but we did have to disassemble the entire vacuum sealer to get the silicone out of the system.

Fishing the stupid piece of silicone out of the vacuum tubing inside the school's vacuum machine.

Fishing the stupid piece of silicone out of the vacuum tubing inside the school's vacuum machine.

And our improvised vacuum forming process? It worked… sorta. The mold stuck like a demon to the PETG, but we eventually got it out. The surface isn’t so nice so I’ll have to sand and polish it. The plastic wrap welded itself to the PETG, so we have to figure out a way to get that off. But we have tested the lid and base, and they do hold a vacuum without crushing! I call that a win.

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Cocktail Science IV: All-Star Shake-off at Pegu Club Testing Shaking Differences Between Bartenders Qualitatively

August 19th, 2009 · cocktails

posted by Dave Arnold

This is the fourth Cocktail Science shaking post. The previous are:
1: Thermodynamics of chilling: why drinks get so cold
2: Temperature, Dilution, and Ice.
3: Why do my shaker cans get stuck together?

We had established in Cocktail Science 2 that the type of ice (within reason) and the shaking style (within reason) didn’t appreciably affect the dilution or temperature of a cocktail. All reasonable shaking styles produced drinks within a couple of percent ABV (alcohol by volume) of each other. If temperature and dilution aren’t the main factors distinguishing shaking styles, what are? Most people think the answer is “texture.”

Consequently, we’ve been asking people a simple question: How the hell do you measure a drink’s texture? Many people propose checking drink aeration by measuring density. I don’t think aeration is the most important aspect of most drinks. Some wanted to check the ice crystals produced by different shaking techniques. Again, are ice crystals the only determining aspect of a drink’s mouth feel? What if we measure density and ice crystals? In the end, all these approaches are flawed because they don’t really address the REAL problem: What does the drink taste like?

We were discussing this with Audrey Saunders from Pegu Club and decided that instead of trying to measure texture, we should get four badass bartenders together, have them shake a standard drink, and see if we could tell the difference. Audrey graciously offered to host the event at Pegu Club last Monday.

The bartenders were:

The Shakers (in alphabetical order, who shook what drink will be revealed at the end): Alex Day, Kenta Goto, Don Lee, and Chad Solomon.

The Shakers (In alphabetical order. Who shook which drink will be revealed at the end of the post): Alex Day, Kenta Goto, Don Lee, and Chad Solomon.

Alex Day, of Death and Co., and the Franklin Mortgage and Investment Co. (and the Tales of the Cocktail shaking seminar!); Kenta Goto, of Pegu Club; Don Lee, PDT, Momofuku Ssam; Chad Solomon, Milk and Honey, Pegu, Flatiron Lounge, Little Branch, etc., etc.

All serious players.

The tasting panel was:

The Panel: Audrey Saunders, Eben Klemm, Nils, and Dave doing the crazy-monkey test-shake

The Panel: Audrey Saunders, Eben Klemm, Nils, and Dave doing the crazy-monkey test-shake

Audrey Saunders, grande dame of the cocktail world, owner of the Pegu Club, and friend of The FCI; Eben Klemm, head of beverage for the B. R. Guest Restaurant Empire, and head of the Tales of The Cocktail Shaking Seminar; Nils; Myself.

 

The drink, as chosen by Audrey: the daiquiri. She intimated that any other initial choice would be preposterous. I wasn’t about to argue.

We decided that the drink would be pre-mixed, so there could be no difference in the mix from bartender to bartender. The recipe was: 2 parts white rum, 3/4 parts 1:1 simple syrup, 3/4 parts lime juice.

Kenta with the pre-mix daiquiri: 2 parts white rum, 3/4 parts simple syrup 1:1, 3/4 parts lime juice

Kenta with the pre-mix daiquiri: 2 parts white rum, 3/4 parts simple syrup 1:1, 3/4 parts lime juice

The pre-mixed drinks were also pre-portioned for each bartender. Each bartender was given identical shakers with 12 total Kold-Draft ice cubes. We didn’t limit how or how long the bartenders shook. That was the point of the test, to see if those factors made a difference. The tasting panel was not allowed to watch the bartenders shake and was not allowed to see the bartenders pour or place their drinks. All drinks were poured into un-chilled fizz glasses. We chose fizz glasses because they allow for easy checking of drink volume. They were un-chilled because we didn’t want to augment shaking styles with additional chilling.

Here is the first shake:

Chad Shaking

Chad Shaking

Alex, Kenta, and Don working

Alex, Kenta, and Don working

The very first shake. All other pictures are presented in the same order.  These are the drinks right after they were poured. The red line is where the crystals and foam stopped. On the bottom is a close-up of the tops. On the top far-right is a glass of measured but unshaken daiquiri.

The very first shake. All other pictures are presented in the same order. These are the drinks right after they were poured. The red line is where the crystals and foam stopped. On the bottom is a close-up of the tops. On the top far right is a glass of measured but unshaken daiquiri.

We didn’t taste this one right away. We wanted to see what happened to the drink texture if we waited. Obviously, Drink 1 had more ice crystals on top and Drink 2 had the fewest. Drinks 3 and 4 look similar. You can’t really judge final drink volume from this shot because of the entrained air. We let the drinks sit for 20 minutes and here is what happened:

First shake (untasted) 20 minutes out.  We tasted them after we took this picture.

First shake (untasted) 20 minutes out. We tasted them after we took this picture.

The drinks have leveled out a lot after they have settled. There are some ice crystals left on top but not many. Drink 1 still has a slightly higher volume, because most of those extra ice crystals have melted into water. We called this effect “secondary dilution.” When the ice crystals are present, they don’t represent dilution, because they haven’t melted yet.

When these drinks were tasted 20 minutes out they were remarkably similar. Even Drink 1 wasn’t that diluted. Audrey expressed a like for Drink 3. Drink 2 tasted slightly more lime-y, sharper, than the rest—presumably because it had a lower dilution and the acid is more pronounced at lower dilutions.

OK, now to taste a fresh shake:

The second shake. We tasted this one right away.

The second shake. We tasted this one right away.

We tasted this one immediately. Notice the second shake looks a lot like the first, except there are more ice crystals in Drink 2. This was the beginning of a trend we saw. The drinks started becoming more similar. This is because we made the crucial error of allowing the bartenders to hear our discussion. That isn’t a mistake we’ll make again. These drinks tasted remarkably similar. Drink 1 had the crunchiest texture. Audrey again liked Drink 3. Eben, Nils, and I liked them all. Drinks 2 and 4 had the most lime flavor, but the difference was marginal. After we had been tasting a while, we noticed that the surface effects, ice crystals, air, were gone after the first couple of sips and the underlying drinks were almost the same.

Here is our first postulate:
Most of the texture and taste differences between shaking styles (in drinks without viscosifying agents like egg) are confined to the top of the glass.

This makes sense because ice and air float. We wanted to test this theory, so we decided to taste the next drink quickly from the bottom of the glass with a straw before we sipped normally. We were out of the original batch, so Audrey had a batch made with cane syrup just to mix things up:

Daiquiri made with cane syrup (sweeter cause the cane was sweeter than the simple).

Daiquiri made with cane syrup (sweeter cause the cane was sweeter than the simple).

Notice Drink 4 is short this time, as is Drink 3. They all tasted similar from the straw, except Drink 4 which was sharper, because the lime was accentuated by the relative lack of dilution. It didn’t taste as concentrated as it looked, however, so I wonder if dome drink accidentally got left in the shaker or spilled. When tasted from the top, the texture difference were much the same as they were for the second shake. The cane syrup made a sweeter drink than the simple, because we didn’t correct for different Brix levels, but it was still balanced. Eben liked Drink 2 best. Nils and I like it boozy so we liked Drink 4, although I also liked the texture of Drink 1. Audrey went Drink 3 again.

Then we did a shake with agave nectar instead of simple:

Daiquiri made with agave nectar (no one was a huge fan).

Daiquiri made with agave nectar (no one was a huge fan).

These drinks are almost identical (excluding surface texture). None of us liked them, however, and we vowed to never again make a daiquiri with agave syrup.

After the official tasting, a discussion of “open gate, closed gate, or half gate?” erupted. I didn’t know what they were talking about so I figured I was about to be let in on a mystical secret. Here it is: Bartenders adjust the amount of ice crystals they let into the drink by controlling how far they push down on the hawthorn strainer as they are pouring.

Hawthorn shaker ninjitsu. Open gate on left, closed gate on right.

Hawthorn shaker ninjitsu. Open gate on left, closed gate on right.

Closing the gate holds back more ice, producing a shorter pour with fewer crystals, and opening the gate does the opposite.

Just for fun, I shook a standard daiquiri using the crazy-monkey technique. The crazy monkey involves shaking so hard and so long that your body feels like it is flying apart. The idea is to see if a ridiculous and unfeasible shake appreciably alters the drink. Here is the drink:

Shaken by the crazy monkey. Look at that aeration! Look at those crystals! Some tasters thought it was too watery. See discussion.

Shaken by the crazy monkey. Look at that aeration! Look at those crystals! Some tasters thought it was too watery. See discussion.

Audrey and Nils thought the drink was more diluted. Eben thought it was a little more diluted, but not so diluted that it was outside the range of normalcy. It did have a lot more ice and air than the other drinks. What is interesting about this is that although the drink was a little more diluted, it wasn’t diluted as much as you’d guess from how crazy I went with it. To me, this was consistent with our results from the shaking seminar.

The monkey shake leads us to the subject of our next cocktail post: our perception of dilution. The crazy monkey did taste more diluted than the normal drinks. If the other drinks were 21-20% ABV, the monkey tasted like 18-17. We couldn’t measure the alcohol, but the truth is, the monkey was probably only 1 or 2% ABV below the other drinks, not 3. From tests we have run earlier, we suspect that there are certain drops in ABV that register more than others. The difference in taste between a 21 and a 20% ABV drink isn’t as much as the difference between a 20 and a 19% ABV drink.

So who was whom?

The shakers revealed.

The shakers revealed.

Don revealed to us that he was doing a modified version of the hard-shake, and intentionally producing copious crystals. Alex had to jet to work before the discussion at the end. Chad and Kenta had no comment. Pegu had opened for business and customers were rolling in, so we hightailed it out.

Till next time.

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Summertime Apples: Pitfalls and Opportunities

August 16th, 2009 · apples

posted by Dave Arnold

For an intro to our apple project, see Two Hundred Apples a Day.

Early Harvest. Really appropriate apple name for this post.  The apple? Eh.

Early Harvest. Really appropriate apple name for this post. The apple? Eh.

Though most summer apples taste no better than their year-round commercially available brethren, there are a few varieties that are a real treat when picked at their peak. Unfortunately most growers bring them to market well before they should. That’s our fault: most consumers will only buy apples that are crunchy, crisp, and hard. Most summer apples worth writing home (or here) about are only crunchy, crisp, and hard when they’re unripe. An unripe apple is an unbalanced apple—starchier, higher in acid and lower in sugar, and less aromatic than it wants to be. When ripe, good summer apples are often crumbly. A crumbly apple can be a very good apple, as the Victorians understood. They had many more apple varieties than we do today, and a good tasting, juicy, crumbly apple was widely appreciated. Today’s would-be summer apple connoisseur will have trouble finding great tasting varieties until we let our growers know that we want ripe, even when ripe means not crunchy.

Prior to the early nineteen hundreds, early-ripening apples were commercially successful because storage practices were not very sophisticated. If you wanted an apple pie in July, the summer apples would be better than the stored apples from the fall. Today we can get decent apples in the supermarket all year long, so a summer apple needs to taste better to compete. A lot of the early apples don’t make the grade. The ones that do need to be picked at the right time. Summertime apples aren’t like fall apples, many of which are hard and crunchy at their peak, a period that lasts long enough to make them commercially viable. Summer apples develop quickly and perish quickly. Here today, gone tomorrow.

Many apples taste completely different depending on where and how they are grown, a fact that compounds the summer apple buyer’s difficulties. I would guess that the apple varieties that have become popular in supermarkets—aside from storing well, shipping well, and looking pristine—also tend to taste similar when grown in different locales under different regimes. The best way to enjoy lesser known varieties, including summer apples, is to get to know a particular grower (or grow your own). It isn’t enough to know that a variety does well in your area, you have to know how it does in a particular orchard. The climate and soil are only a part of the issue; orchard management practices and choice of rootstock greatly influence taste. The key is to taste a whole lot of apples from different growers. Buy whatever you can use from this year’s harvest and remember who grew the ones you like. The season’s very short, so mark your calendar for next year’s harvest (or for the harvest two years from now—a lot of these apples only have heavy crops every other year). We all accept that wine grapes are radically different depending on where they are grown and how the weather was that year. But apples, which are completely ubiquitous, have lost their sense of place.

There are thousands of apple varieties. All were loved by someone at some time for some reason. Most are useless and bad outside their small area of excellence—the fun is in the search for the right apple at the right place at the right time for the right reason.

Below, some notes from our recent tastings:

From Virginia Vintage Apples (a fantastic apple resource.) When we got this shipment on July 27, the apples were about a week old.

Yellow Transparent left, Lodi right

Yellow Transparent left, Lodi right

Lodi and Yellow Transparent:
Like most very early summer apples, these are markedly acidic. Some growers call these ‘salt apples,’ because their high acidity (and, to be frank, relatively flat flavor profile) benefits from a liberal dose of salt. We have tried these varieties two years in a row from orchards in Virginia and New York. The ones in Virginia ripen in July and the ones in New York a couple of weeks later. We don’t like them that much, even though we really want to. The New York ones are marginally better than the Virginia ones (more time on the tree before ripening?). They are very acidic and lemony, with little apple flavor. Perhaps they’d be better right off the tree just before they become overripe. Who knows? They are, in fact, better with salt.

Gravenstein left, Red Astrachan right, two apples that didn't taste like the ones Nils used to get.

Gravenstein left, Red Astrachan right, two apples that didn't taste like the ones Nils used to get.

Red Astrachans and Gravenstein:
Nils was really looking forward to these varieties—some of his favorites in Sweden. He was disappointed, because the flavors were not as he remembered them. It’s hard to judge an apple from a single-orchard tasting. Though genetically identical, the apples out of Virginia bore little resemblance to the ones from Nils’ childhood.

Carolina Red June left, Chenango Strawberry right

Carolina Red June left, Chenango Strawberry right

Chenango Strawberry:
An awesome name for an apple. They tasted good, with a berry-like note in the acidity and a good apple flavor. We really liked the juice—zippy with a cran-lingonberry note. We especially liked it mixed with the juice from…

Carolina Red June (or Juneating):
An old early apple. We enjoyed the apple, but we liked the juice even more. It has a beautiful color, and is sweet and very refreshing. It was lacking a bit in the mid palate until we mixed it with Chenango Strawberry.

Here are the juices from the July 27 batch of apples from Virginia Vintage Apples (We juiced all our apples un-peeled in a champion juicer. We added ascorbic acid immediately to prevent browning and oxidized flavors.  We treated all the juices with Pectinex Smash XXL and spun in a centrifuge to clarify.)

Here are the juices from the July 27 batch of apples from Virginia Vintage Apples (We juiced all our apples unpeeled in a Champion juicer. We added ascorbic acid immediately to prevent browning and oxidized flavors. We treated all the juices with Pectinex Smash XXL and spun in a centrifuge to clarify.)

From the NYC Greenmarket, July 31st (sorry, we lost the orchard name!)

Vista Bella aplle. First year we've had it.  We liked it.

Vista Bella aplle. First year we've had it. We liked it.

Vista Bella: A stand-out in a long tasting that was mostly a bust. We would use it without reservation. It had a really good red apple flavor with floral notes and nice acidity. It almost tasted like apple pie. Its texture was juicy but soft and crumbly, not mealy. It had a nice, thin peel.

Geneva Early apple vacuum infused with apple juice

Geneva Early apple vacuum infused with apple juice

Geneva Early: Very interesting. Flavor was OK; peel was awful—bitter and tannic. But the apple had the texture of a solid applesauce. We peeled it and vacuum infused it with apple juice (Chenango Strawberry). It took to vacuum infusion much better than most apples, almost like a pear.

August tasting notes soon!

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Japanese Fish-Killing: Ike Jime Smackdown Part 2

August 13th, 2009 · ike jime

posted by Dave Arnold

The Results:

If you don’t know Ike Jime, read our Ike Jime saga in Ike Jime Part 1 here.

When we left off, Chef Suzuki had sashimied up a bunch of fish for us to taste. Unfortunately, the fish was really too fresh. The oldest fish in the bunch had been dead only 4 hours and the youngest only 2 (all fish of the same type had been killed at the same time). Ideally, we would have waited at least a day to cut the fish. After death, rigor mortis sets in and the muscles tense up. They don’t relax quickly. Some fish, like salmon, are kept several days before eating so that rigor can “resolve” itself (that’s what the meat scientists say—resolve). More on rigor mortis later. Even though the tasting wasn’t going to be ideal we were hoping to see differences between the techniques. We couldn’t wait till the next day because we wouldn’t have chef Suzuki the next day.

Dave, Chef Suzuki, and Nils

Dave, Chef Suzuki, and Nils

Watching Suzuki cut the fish was a pleasure. On many of his slices he would make an extra—almost invisible—cut meant to absorb soy sauce. Nice stuff.

Chef Suzuki cutting fish

Chef Suzuki cutting fish

Here is what we had:
Small farmed striped bass (all 4 hours dead): Western (no bleeding, left on counter for 20 minutes, hit on head, gutted an hour later), Japanese bled (cut through the spinal cord behind the gills and at the tail and bled in ice water, then gutted right away), and Ike Jime (like Japanese bled but with a needle jammed into the spinal cord.)
Small fluke (all 2.5 hours dead): Western (no bleeding, but hit on the head right after removing from water, gutted an hour later), Japanese bled, and Ike Jime.
Small black sea bass (2 hours dead): Western (like fluke), Japanese bled, Ike Jime (the Ike Jime on this was only partial, it was hard to get the needle all the way down because the spinal cord was so small).
Barramundi: Not tasted (we were going to cook it next day)

We tasted them blind first, and then continued tasting after we knew which was which.

Striped bass, no bleed on top, Japanese-bled in the middle,d full Ike Jime on bottom

Striped bass, no bleed on top, Japanese-bled in the middle, full Ike Jime on bottom

The difference between the stripers was amazing. The un-bled striper’s flesh was obviously ruddy, had a metallic flavor and a mealy texture. The Japanese-bled fish was very clean tasting and didn’t have the mealy texture of the un-bled fish. It was good. The Ike Jime striper, however, clearly had a firmer, better texture. 100% of those present preferred it. If you look at the picture, you can see that the Ike Jime striper has more color than the Japanese-bled. I think this is because it took a while to get the needle in whereas the other fish went right into the ice water to bleed. An alternate explanation is that Ike Jime lessened the force of muscle contractions, and strong muscle contractions help expel blood. In the future, I will place the fish in water to bleed first and then needle it. As an interesting side note, the Ike Jime striper, even after 4 hours, even after it had been gutted, was still twitching occasionally—the muscles were still “alive” as Suzuki said (technically, the ATP, adenosine triphosphate, hadn’t been fully used, and that is the critical issue with Ike Jime as we shall see later).

Fluke, no bleed on left, Japanese-bled on right, Ike Jime not pictured

Fluke, no bleed on left, Japanese-bled on right, Ike Jime not pictured

The Western Fluke didn’t look as bloody as the striper, but the texture was mealy mealy mealy. I had to spit out a part of it, while other parts of the fish were not as bad (I wish I had written down which part of the fish had the worst texture). The Japanese-bled was clean with a good texture (for a freshly killed fish). The Ike Jime fluke was crunchy—like seaweed. Really amazing difference. I don’t think you’d want to serve it that crunchy, but it was good. The theory is that the rigor in the Ike Jime fish will resolve into a better texture the next day.

Black sea bass, no bleed on bottom, Japanese-bled on left, Ike Jime on right

Black sea bass, no bleed on bottom, Japanese-bled on left, Ike Jime on right

The black sea bass had the least difference between the types. It also had the least time between the kill and the taste, for whatever that’s worth. The un-bled bass wasn’t bad—a little mealy. We didn’t get any metallic taste. The differences between the Japanese-bled and the Ike Jime were not as great as with the other fish. This could be because of partial Ike Jime, or because we didn’t wait long enough, or because the black bass doesn’t need the needle. More experiments are needed.

Clearly, the Ike Jime was doing something. I needed to figure it out.

That night, I happened to have a neurobiologist-doctor friend over for dinner. Bob Datta is an MD PhD who is also a food nut. Every year, instead of a birthday party, he throws an “I’m Still Alive” dinner to commemorate the anniversary of his bone marrow transplant. The dinners are legendary. Anyway, he is moving from Columbia to Harvard (he is a real dummy), so I had him over before he left. When I told him about Ike Jime, his first response was “that sounds like bullshit, after you sever the spine what more do you need to do?” So I pulled out my favorite talking-to-a-scientist line: Empirically, there appears to be a difference, so assuming it isn’t bullshit, can you think of a plausible theory for why Ike Jime could make a difference? This question produced the desired state of deep-thinking in Dr. Datta. About 30 seconds later he said “central pattern generators.” What? “CPGs.” What? “Central pattern generators are groups of neurons that contain within them the coding for complete behavioral patterns, like the swimming motion in fish. They don’t require a connection to the brain to work. In fact, the brain inhibits them. When left on their own they want to fire. Killing the brain wouldn’t knock them out.” Bang. I had a plausible theory. I called McGee. He also thought it was an interesting theory.

Then I hit the science databases to look for papers on the subject. I ended up reading about 20. Here’s what I learned:

Many, many people are concerned with the development of rigor mortis in fish. When a fish is killed it still has ATP (adenosine triphosphate) in the muscles. ATP is the energy source that makes muscles (and everything in any living creature) run. It takes ATP to contract muscles, but it also takes ATP to relax muscles. As the ATP starts to run out, the muscle loses its ability to relax, so every little contraction becomes permanently set. The muscle only loosens up again because the muscle proteins themselves get degraded by enzymes and decomposition. The feeling with scientists is that the faster rigor happens, the harder it happens, and the lower the quality in the final product after rigor is resolved. Fast, hard rigor produces fillets with looser flesh, more drip loss, poorer color—you name it. There are many papers on how to delay rigor in fish by preventing struggle and stopping premature ATP depletion (chilling, anesthesia, slaughter technique, etc). Aside from depleting ATP, when muscle activity goes up during the death struggle, lactic acid is produced in the muscle which lowers pH which also supposedly affects quality by lowering water holding capacity (although some current research says pH isn’t as important in fish as it is in mammal meat). A third issue with fish slaughter is that when the fish is frightened or struggling, it releases compounds into the bloodstream which might affect quality. So how does Ike Jime work?

SPINAL CORD DESTRUCTION!

The best paper on the subject I could get my hands on is: Influence of storage temperatures and killing procedures on post-mortem changes in the muscle of horse mackerel caught near Nagasaki Prefecture, Japan, Toshio Mishima, et al. in Fisheries Science, 2005; 71: 187-194 (I can’t post a link because you need an account that can log into the Science Direct database. All you university types can get it. If anyone can get a hold of the Fisheries Science journal number 62 from 1996, there are 3 articles I want to read that are referenced in this article). The technique we have been calling Ike Jime they call “spinal cord destruction (SCD).” I like that—very descriptive. “The fish were killed by making a cut at the brain, letting it bleed, and immediately destroying its spinal cord by the insertion of a piano wire through the neural canal.” Here is the story: Certain fish that swim for very long periods have highly a highly developed autonomic nervous system for swimming (sounds like the CPG’s Bob was talking about). These fish, like bass, like horse mackerel, etc. benefit from spinal cord destruction. Other fish, like plaice, that don’t have highly evolved constant swimming reflexes, don’t benefit (or at least not as much). The paper recommends doing a species by species test to see which fish benefit the most. The paper didn’t mention CPG’s (in fact no paper did that I could find). Someone needs to do some research on that. So then, when you destroy the spinal cord, you destroy the swim reflex, which helps reduce ATP loss, delaying and softening rigor, increasing the quality of the fish. Another interesting point in the paper is that we are probably storing our fish too cold. According to them, fish should be held at 10ºC for 24 hours after slaughter for maximum quality. Voila. Almost.

There is another interesting paper that raises some questions: Pre- or post-mortem muscle activity in Atlantic salmon (Salmo salar). The effect on rigor mortis and the physical properties of flesh, by Bjørn Roth, et al in Aquaculture 257 (2006) 504-510. These scientists killed “rested” salmon by whacking them over the head and then put electrodes in the brain to stimulate muscle movement. They artificially contracted the muscles until all the ATP had been used up. The fish went into rigor very quickly—more quickly, in fact, than similar salmon that they had “stressed” before they killed and much more quickly than salmon that had been “rested” and killed. The electro-stimulated fish also came out of rigor quicker than the other salmon. Here is the interesting part: The quality of the electro-salmon was judged the same as the rested one. The stressed fish were not as good. These authors point out that early rigor alone isn’t what decreases quality. There is some other mechanism involved. They speculate that the absolute force involved in the muscle contractions is higher in stressed and panicked fish and THAT is what cause post rigor texture to be affected. Their electro-stimulation they say, was more gentle on the muscles than the brain of a fully frightened fish.

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Japanese Fish-Killing: Ike Jime Smackdown Part 1

August 11th, 2009 · ike jime

posted by Dave Arnold

Ike Jime is a Japanese fish killing technique. The spinal cord and main blood vessels are severed at the head and tail, a long needle is pushed down the spinal cord, and the fish is placed in ice water to bleed out.

Several months ago, Dave Chang of Momofuku fame called me and said, “We have to investigate this Ike Jime thing. McGee says it’s bullshit.”

I am pretty sure McGee (that would be Harold McGee, master blaster of science in the kitchen) didn’t say that Ike Jime was bullshit, but rather that he couldn’t think of any reason it would make a difference in the taste of the fish. The part about cutting at the head and the tail and allowing the fish to bleed isn’t really in dispute. This technique does get the blood out. The question is: does the needle in the spine do anything? The Japanese insist that the needle is important because it ensures that the muscle “doesn’t know it is dead.” Skeptics wonder what the point of skewering the spine is after the spinal cord has been cut.

Nils and I set out to do some Ike Jime experiments at the school. We needed an unimpeachable expert so we could make sure it was done correctly. Friend of the school Saori Kawano, from Korin knives, put us in touch with Chef Toshio Suzuki, of Sushi Zen in NYC (btw, if you don’t know Korin, check out their website here. Make sure you have a napkin to wipe up the drool). Sushi Zen is one of the most highly regarded sushi restaurants in New York. Chef Suzuki graciously agreed to come in and demonstrate the technique. I confirmed with Chang, made sure Mindy could come, and the test was set up for last Monday.

Chef Suzuki

Chef Suzuki

Here’s what we wanted to do: Get 6 live fluke and 2 dead fluke. We would kill 2 fish Western style, 2 Japanese style without the needle, and 2 with full Ike Jime, and then taste the difference between them and the 2 dead fluke. Chef Suzuki said that the technique would be unnecessary and difficult on the fluke we could get, because their spinal cords would be too small. He suggested bass instead (btw his name means bass in Japanese). OK. We ordered live bass. They didn’t have stripers so we got black bass. I called Dave Chang to re-confirm he could come—yes, but he definitely wanted different types of fish, including fluke. OK. We ordered the live fluke as well.

The day of the test, after Chang and Suzuki had shown up with Taeko Takigami from the Gohan Foundation, I realized that the fish company had taken the liberty of killing the fish for us. I guess they thought they we doing us a favor. Crap. Nils was wrapping something else up and I was staring at a box of dead fish, so I ran like a demon to Hong-Kong Supermarket 6 blocks away. Hong Kong, in the heart of Chinatown, always has live fish in their tanks. That day they had farmed stripers and barramundi. I had to find the guy who spoke English so I could explain that I needed to buy them live and put them in trash bags full of seawater. I was worried, because I have had trouble getting special service here in the past. To my surprise, they agreed. I think they were amused by the idea of some nut running out of the store with trash bags full of water because they were unusually helpful. I blasted out of that place with 16 fish in two big bags. When I got back to the school I thought my arms would fall off.

Live fish in a trash bag

Live fish in a trash bag

And then I found out the fish company was sending over more live fish to make up for their error. Crap. More types of fish made for a better test anyway, I guess. They were bringing live fluke and black bass, and I had stripers and barramundi. We didn’t have any traditional dead fish-store fish (the fish guys wanted their dead fish back in return for the new live ones), so we wouldn’t have that part of our test. Oh well. We set up a giant Lexan of ice water and got to work.

 

Part of Suzuki's knife kit. 2 debas, 2 yanagis, the needle, a saya cover, and another yanagi and deba.

Part of Suzuki's knife kit. 2 debas, 2 yanagis, the needle, a saya cover, and another yanagi and deba.

Listening to Suzuki.

Listening to Suzuki.

First we did our Western-style fisherman’s kill. We took 2 barramundi, 2 stripers, 2 fluke, and 2 black bass and put them in a bucket. They didn’t die so fast so I put them down with a whack over the head—more humane, although it didn’t feel so good.

Chang, Taeko, and I contemplate whacking a striper.

Chang, Taeko, and I contemplate whacking a striper.

Then Chef Suzuki got to work. He picked up a striper and laid it down on the cutting board, head facing right, stroking it a couple of times. “If you are relaxed the fish will be relaxed,” he said. Then he took his deba (a type of Japanese fish knife that I really like), put the point under and behind the gills right next to the spinal cord and pushed in, severing the spinal cord and blood vessels instantly.

Live black bass tend to flare their gills, giving a good view of where to put the knife for the kill.

Live black bass tend to flare their gills, giving a good view of where to put the knife for the kill.

He then pushed down on the back of the knife with his hand until the blade just started to make a mark in the bottom of the gill area and held that position for about 10 seconds. He said that step is important because it helps control convulsions and helps the fish to “continue breathing on its own.” I dunno, that’s what he said.

Pushing the knife down so the fish can "breathe on its own" and not convulse.

Pushing the knife down so the fish can "breathe on its own" and not convulse.

Then he cut through the spine at the tail, making sure he severed everything without actually removing the tail (removing the tail makes scaling more difficult, as I learned later when I accidentally took off the whole tail). Then he took a fine needle and ram-rodded it up the spinal cord from the rear. After a couple of seconds he took out the needle, and immediately put the fish into the ice water. As he did so, he pointed out that you want to keep the body straight but bend out the cut tail and gill part to allow for free bleeding. This, more or less, was the procedure we followed with all of the ike jime fish. The spinal cord on the fluke was, indeed, quite small. We were only able to get the needle into one of them, and not even all the way. Suzuki had us do the technique and tell us right from wrong, so we could do it ourselves next time. The rest of the fish we bled with the same technique but skipped the needle.

 

Here is the technique start to finish in photos:

Holding down a striper. If you are relaxed, the fish will be relaxed.

Holding down a striper. If you are relaxed, the fish will be relaxed.

Put your knife under the gill flap and behind the gills at the top of the fish...

Put your knife under the gill flap and behind the gills at the top of the fish...

... and push down to sever the spine and blood vessels.

... and push down to sever the spine and blood vessels.

Press down on the blade for several seconds.

Press down on the blade for several seconds.

Sever the spine and blood vessels at the tail. Suzuki is about to give the knife a whack with his hand.

Sever the spine and blood vessels at the tail. Suzuki is about to give the knife a whack with his hand.

Shove a needle all the way down the spine of the fish. This is the mystical part of ike jime.  This is supposed to make the muscles "not even know they are dead."

Shove a needle all the way down the spine of the fish. This is the mystical part of ike jime. This is supposed to make the muscles "not even know they are dead."

Needle in the spine, ready to go in the water.

Needle in the spine, ready to go in the water.

Putting a fluke in ice water to bleed out. The heart is still pumping so we are using the fishes own circulatory system to rid it of blood. I am bending the body too much here according to Suzuki. The head and tail should be bent but the body should be straight.

Putting a fluke in ice water to bleed out. The heart is still pumping so we are using the fishes own circulatory system to rid it of blood. I am bending the body too much here according to Suzuki. The head and tail should be bent but the body should be straight.

The fluke water gets rather gory.  We called it fluke punch.

The fluke water gets rather gory. We called it fluke punch.

Finished stripers

Finished stripers

Some notes: the technique of severing the spine by going through the gills is good because it preserves the look of the head. It is also acceptable to cut the spinal cord from above; it just isn’t as pretty and doesn’t have the “press with the knife for breathing” trick. Chef Suzuki put the needle in from the rear because it can’t go in from the front without damaging the head. Nils and I think that going in from the front would definitely be easier if the head doesn’t need to be pretty. Also, getting the needle into the spine is much more difficult if you don’t sever the spine in between the vertebrae. Suzuki was good at this, we weren’t.

Suzuki also showed us the really cool technique of cutting the scales off a fluke using a yanagi (a Japanese fish slicer). I was better at it than I thought I’d be. Of course Nils was good at it. Here is the technique:

Using a yanagi, the scales are cut off of a fluke in a paper-thin layer without damaging the skin.  Serious badass technique.

Using a yanagi, the scales are cut off of a fluke in a paper-thin layer without damaging the skin. Serious badass technique.

Cutting the scales off of fluke. Here is the belly side. First cut off a strip of scales running down the middle of the fish (not shown in this photo). Hold the tail of the fish with your left hand. Hold the yanagi flat against the fish. Don't press into the fish at all. Saw back and forth with the knife to cut the scales in an even strip. Notice the finger on top of the yanagi (in the circle) this helps guide the knife and makes cutting more accurate. After the middle strip is cut, put the fish on the edge of the board and cut off the scales at an angle (shown in this photo).

Cutting the scales off of fluke. Here is the belly side. First cut off a strip of scales running down the middle of the fish (not shown in this photo). Hold the tail of the fish with your left hand. Hold the yanagi flat against the fish. Don't press into the fish at all. Saw back and forth with the knife to cut the scales in an even strip. Notice the finger on top of the yanagi (in the circle) this helps guide the knife and makes cutting more accurate. After the middle strip is cut, put the fish on the edge of the board and cut off the scales at an angle (shown in this photo).

Here is the top side of the fluke being scaled. When cutting the scales off the the far side of the fish, grasp the tail and turn it as shown.  This twist in the fish helps line up the knife along the flesh of the fish and allows for long even strokes. You want the yanagi to make long strokes. If the surface of the fish dries out, wet it a little to make cutting easier (but not on the bottom or it will get slippery!).

Here is the top side of the fluke being scaled. When cutting the scales off the the far side of the fish, grasp the tail and turn it as shown. This twist in the fish helps line up the knife along the flesh of the fish and allows for long even strokes. You want the yanagi to make long strokes. If the surface of the fish dries out, wet it a little to make cutting easier (but not on the bottom or it will get slippery!).

More cool stuff:

Chef Suzuki shows the proper way to hold a black bass, gripping tightly around the gills. Improper holding can get you pricked with the fins, causing a bad infection.

Chef Suzuki shows the proper way to hold a black bass, gripping tightly around the gills. Improper holding can get you pricked with the fins, causing a bad infection.

Cleaning the inside of the fish. Run the knife down both sides of the spine, then scrub under water with a fish brush. The brush is awesome. It really gets the inside clean.

Cleaning the inside of the fish. Run the knife down both sides of the spine, then scrub under water with a fish brush. The brush is awesome. It really gets the inside clean.

At this point Chang had to leave so he didn’t get to taste anything. He vowed to do more tests. “This is just the preliminary,” he said. He has some far-ranging Ike-Jime test schemes that I cannot reveal.

After the fish had rested for a couple of hours, Suzuki San sashimied up some fish for us to taste.

The results? Stay tuned!

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More Cocktail Science: Why Do My Shaker Cans Get Sucked Together?

August 9th, 2009 · cocktails

posted by Dave Arnold

 You’ve no doubt noticed that when you properly shake an alcoholic drink, the parts of your shaker are drawn tightly together by an internal vacuum force.  Why does this happen and how big is the force?

A couple of cool things are happening when you shake.  First, the air that’s in your shaker starts off at room temperature.  As you are shaking, this air gets cooled just like your drink does.  Cooling the air causes the pressure to go down, which causes a vacuum.  That isn’t all that’s happening, though.  Ice is less dense than water.  When ice melts, it actually contracts in volume.  When the volume of liquid plus ice in the shaker contracts, the volume of air in the shaker increases.  Since you aren’t adding more air molecules, increasing the volume decreases pressure, causing more vacuum. Third, as your liquor gets colder, its density increases, again shrinking in volume and creating more vacuum. A third factor may be a small amount of expelled air when the bartender slams down on the cans before the shake.  The last effect is hard to calculate mathematically.

Those are the conclusions.  Here are the gory details.

The internal closed volume of my 28-16 ounce shaker can setup is 842 ml.  Let’s say we start with a standard pour of 100 ml of 80 proof vodka at 25ºC and add 172 grams of 0ºC ice to it. Ice at 0ºC has a density of 0.9167 grams/ml, so our ice volume is 188 ml. Therefore before we shake, the volume of gas in our shakers is 842 ml – (100 ml booze + 188 ml ice) = 554 ml. Let’s assume that the air inside the shaker starts at atmospheric pressure (1013 mbar or 1 atm) and is also at 25ºC. Let’s also assume that no air or liquid escapes while we shake (not such a great assumption, but oh well).  Finally, let’s assume that during the course of a 13.5 second shake, the temperature of the drink (and also the air) goes down to -5.7ºC and 63 grams of ice was melted. I chose these numbers because I have good temperature and ice weight data for a shake exactly like that. See here.

Now we have to figure out the pressure of the gas inside our shakers after the shake. Well, the ideal gas law (remember high school!) says that (pressure) x (volume) = (number of molecules) x (an arbitrary constant that depends on units, called the gas constant) x (temperature).  The shorthand is PV=nRT. At the beginning we know the pressure (1 atm or 14.7 psi—pounds per square inch), the volume (554ml), the gas constant (a crazy number because I am not using standard units), and the temperature (25ºC or 298.15ºK).  Now we can figure out how many gas molecules we have.  Turns out we have 0.136 x 10^23 molecules of gas (aka .0227 moles). We are almost done.  We are trying to find the final pressure so we need all the other values. We know the new temp (-5.7ºC), the number of molecules stays the same as does the gas constant.  All we need is the volume. After calculating the density change of melting ice and the density change of the cooling drink (the density change of cooling ice isn’t so important), the new liquid drink plus ice volume is 280 ml –8 ml less than before. Consequently our gas volume is 8 ml larger than before.

Plug in all the numbers, and the inside of the shaker has a negative pressure of about 1.7 psi. Since the small shaker measures 3 316 inches across, the force to pull the cans apart should be about 13.6 pounds.  Not bad.

Does this fit what actually happens?

Mason jar standing in for a shaker.  I couldn't wait for the small shaker on right to dry (too impatient).

Mason jar standing in for a shaker. I couldn't wait for the small shaker on right to dry (too impatient).

Well, I have some canning jars that hold almost exactly the same volume as my shakers (they are within 10 ml).  Luckily, for me, these jars seal well and already have a 14-inch hose barb glued to them that fits the hose of my vacuum gauge perfectly.  We shook 100 ml of 80 proof vodka with 172 grams of ice and, after 15 seconds, reached a negative pressure of 1.37 psi. Pretty close. I was happy enough. Don’t hesitate to call me out if you see any errors.

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Two hundred apples a day…

August 7th, 2009 · apples

posted by Dave Arnold

It’s apple season! Really, apple season starts earlier than you think. It started almost a month ago already. Next week we’ll start posting our tasting notes on this year’s crop.

This is the first of many posts on apples. We love apples. Apples are delicious. Apples are worth close study. Nils and I even want to do a book on apples. Here is the background on the FCI’s apple project:

The apple orchard at Geneva (aka the germplasm repository).

The apple orchard at Geneva (aka the germplasm repository).

As New Yorkers, it makes sense we would be interested in foods that grow at their best in New York State. Apples are one of those things. I’m not saying that the apples where you live aren’t good, just that New York’s are great. In fact, one of the greatest apple references of all time is The Apples of New York, a two volume set published in 1903 at the end of the golden era of fruit breeding. Read it on Google books here and here. As Americans (and Swedes living in America), it also makes sense that we’d be interested in foods that are deeply entwined in our history –apples fit the bill again. After years of mulling over apples, apple cider, apple history, apple jack, etc, we decided two years ago to do a project on apples. Our first step was to go to the Cornell/USDA agricultural extension in Geneva, NY in the middle of October to taste as many apples as we could.

The Geneva station houses an apple research facility as well as the largest collection of apple trees in the world. They have thousands of types. You can peruse their database here. Unfortunately, Nils had some  meeting he was forced to attend so he had to cancel. Instead, I went to the apple collection with Harold McGee: master of culinary science, space, and time. You can read about his thoughts on the trip here.

This is how we found our way around the orchard.  I printed out an answer key to the whole thing. Calville Blanc D'Hiver, by the way, is a great old French variety.

This is how we found our way around the orchard. I printed out an answer key to the whole thing. Calville Blanc D'Hiver, by the way, is a great old French variety.

Strangely, the guys at Geneva thought that all we wanted to do was see the apple trees. They thought our interest was academic. When we pleaded to be allowed to stay with the apples, they looked at us and said, “You mean you actually want to taste the apples? Nobody has wanted to do that before.” McGee and I looked at each other and laughed. Why the hell else would we drive for 9 hours to the top of New York State? We ended up tasting hundreds of types of apple while we were there.

Flower of Kent.  This is the apple that fell on Issac Newton's head.  You might remember it from such stories as: Coming Up With the Theory of Gravity. Great story, great history, really crappy apple.

Flower of Kent. This is the apple that fell on Issac Newton's head. You might remember it from such stories as: Coming Up With the Theory of Gravity. Great story, great history, really crappy apple.

Here is McGee doing the William Tell with a Flower of Kent.  It's about all that apple is good for.

Here is McGee doing the William Tell with a Flower of Kent. It's about all that apple is good for.

We started with civilized tastes and ended by ripping bites out apples, taking a couple of chews, and spit/spewing the masticated paste out of our mouths in a giant cloud of juice that eventually settled all over us making us smell like a cider factory.

McGee and I after a lot of apples.

McGee and I after a lot of apples.

We were bloated and giddy as we left the orchard that night when it became too dark to read the signs on the trees. We went back again in the morning.

I learned more in those two days of tasting than I had in a lifetime of eating apples. I learned how to tell an overripe apple by feel, that the side of an apple facing the sun has a different flavor than the side in the shade, how thinning the crop of apples on a tree affects quality, how important refrigeration is to maintaining apple flavor and on and on.

Esopus Spitzenburg.  An old, highly acclaimed apple.  Not so good if the tree isn't thinned, as we found out.

Esopus Spitzenburg. An old, highly acclaimed apple. Not so good if the tree isn't thinned, as we found out.

I also started developing an apple allergy to add to my throat-closing cherry allergy. Luckily, I can solve my apple allergy with Benadryl (so far). I was pounding Benadryl like candy the whole time I was in Geneva. Strangely, I am only allergic to some apples. I found out from doctor Susan Brown, an apple professor at Cornell, that scientists know which varieties of apples are more likely to trigger allergic reactions, they have just never published the data. Awesome. She also showed us some new apples she was working on: one tasted like anise and another was balanced in flavor but had over twice the amount of acid and sugar as a normal apple—apple on crack. Those really were awesome. They didn’t have names so you’ll have to contact her if you are interested.

McGee and I loaded up bags with a couple of dozen of the most promising varieties and headed back to The FCI where Nils and I tasted, baked, and juiced every apple we brought back. That’s when we made our first big apple culinary leap.

For years we had been using Granny Smith apples for juicing in the kitchen. They are tart and the juice looks good (if you use ascorbic acid to keep it green). It was our go-to juice apple. All that changed when we tasted the juice from Ashmead’s Kernel. Ashmead’s Kernel is an undistinguished looking russet apple that hails from early 18th century England, the world’s other apple-breeding superpower. It produces the finest juice I have ever tasted—rich, tart, complex, powerful. Then we got lucky. Nils found an orchard that produces great Ashmead’s Kernels that has distribution in New York City, Poverty Lanes Orchards of New Hampshire. I think we bought the rest of their remaining crop. We were swimming in Ashmead’s Kernel and we were happy. The problem was, when the Ashmead ran out, we were no longer happy with the Grannies! They are complete one-note Nancies by comparison—tart and apple-y, but nothing else.

Ashmead's Kernel.  Our holy grail of juice apples.

Ashmead's Kernel. Our holy grail of juice apples.

The Ashmead's Kernel tree in Geneva

The Ashmead's Kernel tree in Geneva

That was only the beginning of our apple journey. There is more to come.

Here is a drink we made using Ashmead’s Kernel for a group of Kaiseki chefs who were visiting The FCI from Kyoto in October 2007:

The Kernel:
Ingredients:

Ashmead’s Kernel Apples
Ascorbic acid
Pectinex Smash XXL
Bulleit Bourbon
Carbon Dioxide

Technique:

Run the bourbon through a rotovap to remove the non-volatile oak. We love bourbon as it is, but the heavy oak tends to wipe out varietal notes of the apple. In this drink we wanted clear bourbon. Sorry to the purists.

Juice the apples with a champion juicer into a container with ascorbic acid. The ascorbic acid prevents the juice from turning color and developing oxidized flavors. Add 1.5 grams of Pectinex Smash XXL per liter of juice. Pectinex is an enzyme that breaks down the pectin in the juice and lets it clarify by itself. See here.

Mix clarified juice and clear bourbon to taste, chill to 0 degrees C and carbonate at 40psi.

Done.

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Just another flavor separation technique

August 3rd, 2009 · Uncategorized

posted by Mindy Lvoff

As I was discussing how to describe (and understand) “countercurrent chromatography” (CCC) with Dave and our friend, Philip Preston of Polyscience (who stopped by FCI today to hang out for a while), Philip summarized the process as “just another flavor separation technique…”  Easy to say when you’re a genius, but I needed a little more detail.  Dave continued that where our centrifuge separates based on density and our rotovap separates based on volatility, CCC separates based on polarity.  The good people of Cherry Instruments have been working on a way to use liquid-liquid CCC in relation to food and flavors, hoping that perhaps this gadget will eventually make the leap into the kitchen.  At some point, Dave will chime in and fully explain what the process is, but in the meantime, here is my best attempt at a layman’s explanation (and thus the depth of my understanding): our Cherry Instruments friends are using a centrifuge to hold oil (non-polar) in place as they pump a polar liquid such as ethanol or water through the oil like a filter – thus the “liquid-liquid” designation.  Different flavor compounds with different polarities will pass through the oil filter at different rates, with the most-polar coming through first with the polar liquid.  Therefore, where our current methods of separation (rotovap & centrifuge) allow only subtle flavor separation, whereas the liquid-liquid CCC process, Dave explained, “allows us to separate and layout different flavors like piano keys.”

Coffee, Spearmint & Menthol oil, & Oregano oil separated into different flavor notes using Countercurrent Chromatography

Coffee, Spearmint & Menthol oil, & Oregano oil separated into different flavor notes using Countercurrent Chromatography

We were given 3 different compounds that were broken out into their many flavor components: Coffee, Spearmint & Menthol oil, & Oregano oil.  For these, ethanol was used as the polar liquid.  The 3 coffee vials that we tasted broke out smokey notes in one, bitter notes in another, and a slight sweet note in the third.  The mint oil was a much more forceful demonstration with one vial basically tasting like pure menthol.  If you’ve never had straight menthol, it’s a little like shoving a Costco-sized package of menthol throat lozenges in your mouth at once.  Luckily, we had already tasted straight menthol before, so we were just upset vs. shocked by the experience.  The oregano oil was the worst, but luckily we could barely feel our tongues, let alone taste much, after our bout with the menthol.  Bitter oregano notes taste like oregano that’s been boiled until dead and then burned at the bottom of a sauce pot.  By the time we were done, all I could taste and smell were smoke, menthol, and bitter oregano.  It reminded me a little of college.

An innocent looking vial of menthol-flavored pain

An innocent looking vial of menthol-flavored pain

The flavor note tasting, while traumatic, did help illustrate the CCC possibilities: you can either isolate a flavor note that you want to use specifically or conversely, remove one flavor element such as bitterness that detracts from whatever you are breaking down.  In our case, we thought of our Habanero Vodka technique and suggested trying to remove the capsaicin from Habaneros, or perhaps even isolating out some of the floral notes.  We also thought of removing the tannin flavors from teas.

What else do you think the good people of Cherry Instruments should try and separate???  Send us your comments and we will pass them along and keep you updated on their progress!

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Espuma, what?

July 31st, 2009 · Espuma

posted by Nils Noren

Cream espuma?

Cream espuma?

“Foam is a culinary technique invented by Ferran Adria”. That is what comes up if you look up foam (culinary) in Wikipedia. What about whipped cream (which I happen to like a lot)? Did Ferran invent that? Mousse? Meringue? Don’t think so. By the way don’t get me wrong, this has nothing to do with Ferran, I couldn’t have more respect for the man and what he does. But it’s a fact that foams have been used in the culinary world for A LONG TIME. Just wanted to set that straight first.

Ferran invented foam?  Who knew?  We love Ferran.  Credit him for his amazing new applications of foam instead.

Ferran invented foam? Who knew? We love Ferran. Credit him for his amazing new applications of foam instead.

Now to the real reason for this post. Why do some people in English speaking countries insist on calling foams espumas? It sounds good on a Spanish menu, but on a menu written in English, not so much. In fact it sounds gross, like someone is spitting in my food. And why all of a sudden stop using a perfectly fine English word that has been around for a long time and replace it with a Spanish word? Or is espuma only related to foams that come out of an Isi bottle? If you put a product made in a kitchen in New York into a bottle made by an Austrian company that’s manufactured in China (we checked on the bottle) and turn it in to a  foam, all of a sudden it should have a Spanish name? Makes no sense to me.

Since we are on the subject of foams. I can’t help to finish with this. If you are going to put air into your food, make sure that you start with a flavor that really needs to be diluted; because air has no flavor (if it does, probably not so good). I know this is obvious but it still happens that I get foams where the flavors are too diluted.  I think that is why foams get such a bad rap.

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Centrifugation: Spin it Faster. More More.

July 30th, 2009 · centrifuge

posted by Dave Arnold

We asked for comments on centrifugation and got some really great responses—so many, in fact, that we wanted to do another post.

If you don’t know about centrifugation (what’s a rotor, what are g forces, why the hell should I care, etc., etc.) see our other posts here and here.

To recap, we have two useful centrifuges, the Sorvall RC-2B and the Jouan C412:

Our two fuges, Big Mama RC -2B on left, Baby Jouan C412 on right.

Our two fuges, Big Mama RC-2B on left, Baby Jouan C412 on right.

The RC-2B is an awesome workhorse. It is refrigerated, built like a bomb shelter, and, with the right rotor, can do  48,000 g’s as 20,000 rpm. The disadvantages are that it is very large, and with our current GSA rotor we are limited to 1.5 liter batches using little bottles with fairly narrow necks (they are hard to fill and clean out). We love it to death, but all in all, it is difficult to see a restaurant dealing with such a large piece of equipment.

Our C412 is not refrigerated, but is smaller, cheaper, slows down quicker, has swinging bucket rotors, and can do 3 liters at a crack. The maximum number of g’s it can pull is about 4000, but 4000 g’s has been sufficient for a lot of our work. We have been using plastic bags to line the rotor buckets. They are cheap and easy to load but aren’t as neat as bottles and tend not to work well on things that don’t form hard pucks like nuts do.

Kalamata spun in a bag. Not as clean as in a bottle.

Kalamata spun in a bag. Not as clean as in a bottle.

See what a mess the kalamata olives are in a bag? In a hard bottle you get three clean layers: brine (awesome), flavorless pulp (garbage), and cured kalamata oil (awesome). We need to figure out a way to make a hard, thin, cheap plastic liner for the 750 ml buckets in the Jouan (advice welcomed).

As for refrigeration, several readers suggested putting the fuge in the walk in fridge. A good idea. We just got a new walk-in recently, so I might just have the space. We’ll let you know how it works.  The reason you want refrigeration, by the way, is that the friction from spinning heats up the rotor, buckets and machine.  Refrigeration fixes that.  Another option is pulling a vacuum on the fuge. This keeps the friction down and, as schinderhannespointed out, allows you to do centrifugal evaporation.  Next fuge.

SPECIAL HELP NEEDED: Today our Jouan, which had been spinning at 4200 rpm nicely for a while, suddenly started topping out at 3200 rpm. Before I rip the machine apart, do any readers have suggestions?

We purchased the Jouan for several reasons:  We wanted a centrifuge we could take to demos.  We wanted a centrifuge that has a large capacity.  Most of all, we wanted a centrifuge that other chefs might find useful.  We also got a great side benefit: we can spin our RC-2B faster than before without worrying. If you have read any of our earlier posts on centrifuges you know we are concerned with metal fatigue. Our rotors are made of aluminum—old aluminum, which could break apart at any second if subjected to too many g’s. The GSA rotor in Big Mama fuge was rated for 27,000 g’s when it was new. We had been running it at 4000 g’s (5000 rpm) because we figured there was no chance of failure at that speed. If we ever DO have a failure the fuge would be destroyed. The rotor would fly apart and completely ruin the whole machine. Now that we have another fuge that can do 4000 g’s, we have pushed our RC-2B up to 10,000 g’s (aw yeah). 10,000 g’s is still well less than half what it was rated for new, so we feel safe. Even if we throw the rotor, the damage would be contained inside the fuge.  We would lose the fuge, but we would still have another one, and no one would get hurt.

So now, assuming we can fix the Jouan, we have a 4000 g 3 liter fuge and a 10,000 g 1.5 liter fuge. Now we have to think of applications. Our readers helped us with ideas.  Before we get serious let’s get stupid.

The Stupid:
One of our original tests was to spin avocado puree to see if we could get avocado oil. We couldn’t. It didn’t work at 4000 g’s or at 8000 g’s. All we got was really smooth guacamole. I mean REALLY smooth guacamole. I was very discouraged by the lack of oil and got in a weird mood, so for giggles we spun whole avocados just to see if they would crush

Whole avocados balanced for spinning. We know it's stupid

Whole avocados balanced for spinning. We know it's stupid

Whole avocados 4000 g's 20 minutes.  Stupid.

Whole avocados 4000 g's 20 minutes. Stupid.

Not as impressive as we had hoped.

The problem with making avocado oil is that the oil is contained within the cells and the fuge isn’t powerful enough to break the cell walls. Even the Vita-Prep isn’t sufficient to break the cell walls. Kent Kirshenbaum, our chemistry professor buddy from NYU and the Experimental Cuisine Collective, suggested putting the avocado through several freeze- thaw cycles.  The ice crystals that form each time you freeze the avocado make lots of tiny holes in the cell walls. Another idea Kent and reader Paul A. suggested was to hit the avocados with our 400-watt Branson ultrasonic homogenizer. The ultrasonic homogenizer (aka the sonic cell dismembrator—how cool is the term cell dismembrator?) is a machine that does two things. It sends people running from the room in agony because of the piercing noise it produces; and it shakes back and forth so fast and so hard that tiny bubble are formed in your food that break with enough force to mash things up very, very finely. We tried both. They both worked. Ultrasound won for yield (it was also a pain in the butt to freeze and thaw, freeze and thaw, freeze and thaw):

Ultrasonically homogenized (400 watts, 5 minutes, 500 grams) and spun (10,000 g's 20 minutes).

Ultrasonically homogenized (400 watts, 5 minutes, 500 grams) and spun (10,000 g's 20 minutes).

The problem with both techniques is that even when the avocados were heavily pre-treated with ascorbic acid to prevent oxidation, the act of breaking apart the cell walls produced some funky, nasty flavors. The oil looked great but tasted like old artichoke, not fresh avocado. Maybe if we cooked the avocado first?

Avocado oil.  Looks great. Taste, not so much.

Avocado oil. Looks great. Taste, not so much.

 

Herb oils:
Several people asked about cleaning up herb oils. We didn’t have much luck at cleaning up herb oils at 4000 g’s, but 8,000 g’s did some nice stuff to this basil oil:

Basil oil. Left side spun at 8000 g's 15 minutes, right un-spun.

Basil oil. Left side spun at 8000 g's 15 minutes, right un-spun.

The spun oil was not only clearer, it had an amazing ruby color and tasted much cleaner and less bitter, if slightly less complex than it’s un-spun counterpart.

Citrus and Other Essential Oils:
We have not had any luck with citrus oils.  I had mistakenly said we had tried to extract citrus oils using alcohol. As Paul A. pointed out, you don’t want to use alcohol, cause that will dissolve your oil.  I think he is right.  Looking back on my notes we DID use water. We ran orange peels blended with water at 4000 g’s for 20 minutes with no results.  The stuff tasted like it would make a great bitters so I made a note that we SHOULD try it with alcohol.  I still want to make a good citrus oil.  The best book on distillation I own is from 1871.  The bad news is it is outdated.  The good news is that it is free in the public domain on Google Books. On page 355 of A Treastise on the Manufacture and Distillation of Alcoholic Liquors by Pierre Duplais, the methods of obtaining essential oils are discussed: expression, which is what the fuge can do; distillation; and maceration in fat (fat washing/enfleurage). He then goes on to explain the differences in flavor between the techniques and when you should use them.  Turns out expression should work fine for citrus oil.  We should be able to zest a whole bunch of citrus and just press it out.  Again, I haven’t had any luck.  Maybe at 10,000 g’s with a homogenizer.   We’ll keep you posted.  The problem we are having with citrus would, I assume, translate to any other product that requires us to separate a very small amount of oil from a large amount of dry/liquid matter.

On essential oils without a centrifuge:

I have been wanting to do super-critical CO2 work for some time but have not had luck finding a unit or figuring out a safe way to jerry-rig one.  Any thoughts?

 I tried butane extraction like they do to make “honey oil” from swag pot, but didn’t feel safe and had no luck. 

I have also never set up my rotovap as an essential oil recovery machine.  Maybe some day. 

The most exciting thing with essential oils and flavors we are working on now is a really cool form of chromatography.  More on THAT soon. 

Nut Oils and Sugar/Water

Mindy mentioned in the last post that we were getting some interesting results from spinning nuts to recover nut oil.  We are planning on actually selling pecan oil out of the restaurant (if we are allowed to).  Why pecan? It is delicious, it is American, and we’ve never had it before. Anyway, we noticed that adding simple syrup to the mix before we spin drastically increases yield of oil. The oil we get is way is much clearer, sometimes less bitter, but always less intense than the oil we get without simple syrup.  Take a look at macadamia nut oil spun with and without simple syrup:

Macadamia oil without simple on left, with simple on right.

Macadamia oil without simple on left, with simple on right.

Wow. Big difference. 

Here is how this simple syrup thing happened:

When you spin nuts you first liquefy them in a Robot-Coupe then ultra-pulverize them in a Vita Prep.  This breaks up the nuts and also heats them up a lot. The nuts get so hot that we no longer toast them beforehand.  They are “blender toasted.” Hot nuts are more fluid than cold nuts, so we like to spin them warm.  When you spin pecans this way, you get a layer of oil, a layer of super-primo nut butter, and a layer of pecan paste+skins.  The skin layer is bitter so I separate it out to use in sweet pastries, etc.  One day, the primo butter got mixed in with the 2nd quality stuff.  That sucked.  I figured let’s re-spin it to try and separate it again.  It was too thick to spin so we added simple syrup.  The results are below:

Pecan on left without simple. Classic three layer pecan --oil, first quality butter, bitter chaff butter. Pecan on right with simple syrup, high yield of oil and a pecan brick.

Pecan on left without simple. Classic three layer pecan --oil, first quality butter, bitter chaff butter. Pecan on right with simple syrup, high yield of oil and a pecan brick.

Wow.  The one on the right had ALREADY been spunonce and still yielded more oil than the fresh-spun batch on left.  Look how clear the oil is!  Weird.  Look how solid the hockey puck of paste is. That extra oil that comes off of the pecans isn’t as heavily flavored as the regular stuff.  FoodPlayer asked if removing the extra oil from the paste makes the nut paste more flavorful.  I guess it does, but it is hard to say because the texture is so different.

We ran another experiment with cashews (I said pecans but one of the interns mis-heard me, oh well).  This time we wanted to measure the effect of simple syrup versus water and the effect of varying the amount of simple syrup. Here it is:

Cashew butter (oil drained). Left to right, 400 g cashew, 311 g cashew plus 89 g  simple 1:1, 350 g cashew plus 50 g simple 1:1, 350 g cashew plus 50 g water.

Cashew butter (oil drained). Left to right, 400 g cashew, 311 g cashew plus 89 g simple 1:1, 350 g cashew plus 50 g simple 1:1, 350 g cashew plus 50 g water.

The water didn’t incorporate as well as the simple syrup. Overall the simple syrup was more effective.  Some of our readers weighed in on this phenomenon. Shinderhannes wrote: 

The most effective additive to help break [a tough] emulsion is a few mls of methanol (stop, don´t try this but ethanol (go head) does the trick as well.

Therefore maybe adding a shot of booze to the nut puree will work like a charm!
As you certainly know, but maybe not all readers, glucose is a poly-alcohol, from a chemical standpoint, so maybe that does explain why SS is so effective….

Great advice. We plan on running more tests soon

Still to Try:
Foie Gras, suggested by Shinderhannes and Jeremiah (Shinderhannes also suggested liver sausage. Nice)

Chorizo (I think that would be good) suggested by Alex T.

Fish oil, suggested by Derek.  Don’t know how to do this one, but would be fun.

Chilled Ouzo, by Shinderhannes.   See the Ouzo Effect. Could we just water it down, precipitate the oil and spin it?

Stuff I don’t know how to do/ have other techniques for:

FoodPlayerasked about milk/cream.  That will definitely work but we have a small cream centrifuge for that.  If you have a specific application (like a really nice milk) it would be worthwhile. I dunno.  Hit me back with more ideas.

Derek asked about cereal grains/hops.  I can’t figure a way to do the grain.  The hops work great in a rotovap, and I’d bet we could do other forms of distillation/etc, but I think we’d run into problems in the fuge.

Thank you for your help. Please keep the comments coming.

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