By Dave Arnold
You can infuse flavors into liquor (and water based things, too) almost instantly with nothing more than an iSi Cream Whipper . You can use seeds, herbs, spiced, fruits, cocoa nibs, etc. Here’s how:
Put room-temperature booze into the cream whipper. Add herbs, seeds, whatever. Close the whipper and charge it with nitrous oxide (N2O –the regular whipped cream chargers). Swirl gently 30 seconds and let stand 30 seconds more. Quickly vent the N2O out of the whipper, open it, and strain out the infusion. Done.
I did a 5-minute knee-slapping song-singing jig around the school when I figured out this technique. It’s really good. I like it better than vacuum infusion for some products. Plus, a vacuum machine will set you back 2 grand.
I got the idea from a technique emailed to me by Mister Fizz. Mister Fizz does rapid marination using pressurized CO2. He gets chicken strips to soak up a heap of marinade real quick. Pretty nifty. Here is a YouTube video. I figured if you could force liquid into foods using pressure, maybe you could also force flavor out.
Here is what I think is happening:
When you charge your whipper with nitrous oxide, high pressure forces liquid and nitrous oxide into the pores of your flavorful food (your seeds or herbs or what-have-you.) When you suddenly release the pressure inside the whipper, the nitrous forms bubbles and escapes from the food quickly, bringing flavor and liquid out with it.
Use room temperature food and liquid. In our tests, cold liquid made for weaker infusions. The cold infusions were slightly clearer than warm ones, but I think that’s because they were weaker. I suspect the bubbling of the N2O is less violent in colder products; the violent bubbling is what brings out the flavor.
Use N2O, not CO2. CO2 can leave some residual carbonation and flavor in your liquor, N2O won’t (there might be a slight sweetness from the N2O, but it will flash off pretty quick in room temperature liquid).
In our tests it didn’t seem to matter whether we vented the whipper quickly or slowly, although I persist in believing that quicker venting is better because of the violent bubbling effect.
We tested infusing a mixture of orange peel, Thai basil and cilantro into rum for 30 seconds, one minute, two minutes and three minutes. We swirled the containers every 30 seconds during the tests. The one-minute batch tasted best, 30 seconds was weak, two minutes was a little bitter, and three minutes was bitter and grassy. I suppose the optimum infusion time is different from product to product, but we know for sure that infusion time matters.
The amount of liquid in the whipper and the number of N2O chargers you use also makes a difference. Our standard batch was 120 mls of liquor in a one-liter whipper using one N2O cartridge. Tripling the amount of liquor to 360 mls resulted in better balanced, but weaker, infusion. We boosted flavor in the 360 ml batch with a second N20 charger. Using 2 chargers in the standard 120 ml batch made a harsh infusion.
Cream whippers are better for this technique than soda bottles, even if you have a large N20 tank like we do. The large mouth of the whippers is extremely useful.
If you crush green herbs before they are infused, the infusion might turn brown over time. Ascorbic acid might help but will also alter flavor.
The standard recipe:
120 mls white rum
3 grams cilantro leaves
8 grams Thai basil leaves
8.5 grams orange peel
Charge with N20, swirl for 30 seconds. Allow to infuse for 1 minute total, then vent and strain.
Other flavors we tried, using a 1 minute infusion into vodka:
Star anise made a strong infusion with a smoky note and lots of color.
Sliced jalapenos made a very spicy infusion that also captured the green notes of the jalapeno. It had much more actual jalapeno character than traditional infusions we have tried.
Sliced ginger produced an infusion that was light in flavor but clean, similar to ginger ale. Our slices were somewhat thick; thin slices might produce a stronger infusion.
Fresh bay leaves didn’t taste great, but might be good with something else. Bay leaves didn’t infuse well till they were crushed.
Sliced carrot infusion picked up a lot of color but not a lot of flavor. The flavor the infusion did pick up wasn’t great.
The best we saved for last. This little gem was Nils’ idea:
Cocoa nibs made a cloudy but very flavorful infusion. If you let it settle for a half hour, it clears up substantially. A miraculous thing about the nibs infusion — it’s not bitter, just chocolate-y. Apparently, it takes longer to extract the bitter flavors than the chocolate ones.