Checked the ice cream again. I noted earlier that it seemed a little grainy and now I can almost taste the starch, albeit almost flavorless in the first place, in the product so I would say that yes retrogradation is definitely happening. It did however take much longer than what I would normally expect for a bowl of ice cream to melt. Once I try again and attain a similar stretchiness to what you were seeing then maybe I can look more into the retrogradation.

http://www.foodinnovation.com/FoodInnovation/en-US/Our+Products/Potato+Starches.htm

I’m inquiring about some free samples from them right now, especially a product called “Perfectagel MPT”.

In regards to submerging in the water I was curious because the potatoes didn’t have that typical “tackiness” that steamed potatoes do. They didn’t feel like boiled potatoes either, but the “tack” was definitely not as prevalent. Note here that the gel created by combining 40 grams potato starch with 200 mL water and cooking creates a gel with surface properties similar to a steamed potato. The gel was quite “tacky” on the surface.

I’m not completely sure what you mean by you let “them flash off steam as they cool…”

I wanted to try the potato starch by itself, but potato starch isn’t made by cooking a potato. Since the cooking is necessary in your recipe I thought I would try that first.

Next set of experiments will be with the potato starch uncooked blended directly into the base. My concern here is it being uncooked.

Then I will try a batch where I cook the potato starch with the base (probably add after the tempering of the eggs and cook for 10 minutes or so with the base). My concern here is that the starches may not gel properly due to over-hydration(?) or fat interference.

I’ve considered also attempting to cook the potato starch in milk (instead of water) in the first place to make a gel. Then shearing it and blending in the base. I’m curious as to the gel properties here and how the fat would interfere with the matrix.

Finally, I would like to just try another version of what I already did but double or triple the amount of potato starch (same amount of water), making thicker more viscous gels. Then shearing these into the base.

I’d be interested to try this with other starches as well. Do you know if any other starches form similar gels when cooked down like the potato starch? I could post a pic or two in the forums at the end of the week of the gels that I’m shearing.

In regards to retrogradation:

1. It is hard to tell with the potato starch ice cream. As I stated before it didn’t quite get the same stretch as you had gotten with potatoes using the potato starch. So, it is hard to tell from a stretch standpoint how much retrogradation has happened. Although, I do find that the mouth-feel of the ice cream doesn’t necessarily feel the same as it did yesterday. It almost feels as if it has become more granular. I’ll check it out again in about 8 hours to see what it is like – that will be around 24 hours post-finished product.

2. I am going to make a simple potato starch gel as I did for the initial experiment and just leave it out overnight to see what happens.

For comparison I quadrupled the recipe Dave has listed above minus the potatoes. I also didn’t quadruple the vanilla (didn’t have that many and wasn’t buying them at the grocery store at 2 for $20…!!!). I expected because of this that I would probably taste potato.

First I made just plain ice cream with it. Yes it was a little TOO flavorful.

Next, I tried to add the potato. This didn’t quite work as well as it did for you guys at the FCI. It did appear to gain some stretchiness, but nowhere near as much as the pictures you have posted. I didn’t have an appropriate steaming vessel with me at work so I utilized a pasta pot with strainer and attempted this. The potatoes may have submerged in the water for a short period of time while I was out of the room. Could this have been the downfall here? And obviously it tasted like potato since there wasn’t enough vanilla in it.

I also tried to just utilize a large quantity of Resistant Corn Starch 260 from Netrition.com. No luck. No stretch and it tasted, well like corn starch. It also left you feeling like you had a hairy tongue, which is absolutely gross! I tried to cook this in some water (brought to simmer), but it just dissolved and once it cooled it began to separate out of the water.

Finally, I’ve been playing with potato starch a lot lately in the forums attempting with KennethT to make an edible biodegradable potato plastic (something he had at El Bulli). We are on the right track there, but it got me thinking about the cooking process of the potato starch. It becomes very gelatinous when heated with just water. The addition of an acid and glycerin makes it plastic.

So, I took 40 grams of Bob’s Red Mill potato starch and added it to 200 mL of distilled water and cooked it until just before a boil. At this point the solution thickens quickly. I then cooled this solution in a styrofoam cup. Once cooled it came out of the cup in a large jiggly mound of opaque gelatinous weirdness! I figured if I could shear it in the blender back into a liquid state then I could add the anglaise and try it. It sheared wonderfully and incorporated into the anglaise great. This was by far the closest I got to making stretchy ice cream as you did.

It didn’t have “enough” stretch though. But, the flavor profile was spot on. The potato starch gel added no additional flavors as did the steamed potato and corn starch. The final consistency was more palatable as well.

Next week or the week after (when time and money permits) I will attempt another round of trials unless you guys beat me to it. I want to double the amount of potato starch to 80 grams/200 mL water and try that and possibly move up from there.

**Click my name for new gastronomic alchemy videos!**

Will post results over the next week or so.

Using pregelatinized starch may also be the way to go. It is worth a shot.

Let me know about those articles as well.

I just got my resistant corn starch 260 in the mail today. It was really cheap ($3/lb – $8/lb shipped – ordered only 1 lb). It is a large amount of powder.

First try with this will be based on the idea that potatoes, when cooked and cooled, increase in resistant starch to about 10%. I will use Dave’s stretchy potato ice cream recipe and based on the resistant starch being 10% I’ll use 22.5 g of Resistant Corn Starch 260.

Jason, do you mean making your own pre-gelatinized starch?

I might have missed it from the above, but instead of using a modified or resistant starch, why not use a pregelatinized starch that is added to the cooled mix and let hydrate for 5-10 min before freezing?

It will be a few days before I have any LN2 access as well (possibly up to a week). I will definitely get back to you on my results.

Also, what about just utilizing potato starch or making a slurry of potato starch and water, heating it and then cooling it…?