(I could not find the Recipe, but I am going to Experiment before Minicon 33 (Bwahahaha!))
This first Recipe is Simple Winging-it from my knowledge of food and Cold Things. To be updated when I actually do this. [I did this at Minicon 33 and it worked smashingly, I will revise but a little - mwg]
Ingredients:
(Regular Malt Ingrediends should be purchased in Regular Malt Amounts, except Ice-Cream, since their isn't any, replace with the dairy stuff.)
Stirring Person:
Use Hotpads. I know, but they insulate either way. Only touch non-insulated items with LN2 in them, with the protection. Unlike churning regular Ice Cream, when the rock salt melt can make some metal surfaces damagingly cold, LN2 starts out quite a bit more damaging (-320 F, -196.2 C, 77K - That's right you natural Science wonks, only 77 Kelvin!)
LN2 Pouring Person (Possibly Same person if Stirring container is heavy or affixed to surface somehow):
You can possibly avoid hotpads, especially since you might not have several pair, and you have a nice handle on anything non-insulated you are pouring from.
Place ingredients except LN2 in Container unlikely to shatter from wide temperature differentials and Stir. Pyrex!!!!!
Continue Stirring after ingredients are mixed and pour in LN2. Use a Pyrex container with a lip to easily view the amount of liquid pouring into the mixing container and to keep the liquid away from the hand of the stirring person. Stir In LN2 until the desired consistency has been reached.
All the LN2 will "burn" off and none will be left in the drink after stirring. Gaseous Nitrogen, that dangerous stuff that makes up 72% of what we breathe, will, however, be left in somewhat higher quantities than a normal shake. This will keep it from oxidizing nicely if you were worried about it turning to vinegar or something, since nitrogen is frequently what is used to keep wine and other delicate foods fresh.
This recipe might also be applied to other physically appropriate foodstuffs, though we haven't thought of them yet.
Going camping once many moons ago (SCA Warlord 1991), we (friends who share regional discovery rights and I) used Dry Ice (Carbon Dioxide (CO2) in its solid phase, -64F (Do the math for the other units yourself) in the bottom of our cooler to keen the water ice solid. After the first day of camping we noticed something "funny" about the taste/consistency of the fruit, particularly cherries, we were storing. When you bit into them, there was a tingly sparkling sensation in your mouth and on your tongue.
What had happened was that the normal atmosphere (air) in the cooler had been replaced with an almost 100% pure volume of that evil greenhouse gas, CO2. For the uninitiated (few of you probably) dry ice goes directly from solid to gas phase in a process refered to as sublimation (v. to sublime). Anyway, the fruit having various degrees of permeability to CO2 gas, participated in a gas-exchange by diffusion across their several membranes. This left rather sparkly fruit after being sequestered in the CO2 for a number of hours, not less than 4. Diminishing returns on carbonation come after about 12 hours.
Some fruit works better than others and cherries are among the best. Just as some people soak various fruit in liquid alcohol (to get the best of both worlds somehow delivered by vodka and cherries) have discovered, some fruit is not too permeable. Some fruit works better peeled or sectioned, and the CO2 is neutral enough that the fruit will not brown as fast with exposed cloven faces, since the oxygens are relatively happy being on the CO2 as compared with molecular Oxygen (O2). However, some oxidation can happen. Citrus, pulled apart into its natural section, works well, however. (Historical Note on Previous Sentence: A couple billion years of anaerobic life on this planet weren't crawling up that big an energy gradient just to live. Not to mention current plants.)
Hints/Pitfalls:
Don't use a truly airtight container. The solid form of CO2 is "a bit more compact" than the gas form.
Bananas don't work. They oxidize too fast when cutting them up and don't carbonate through the peel. And its a shame too, I love them.
Strawberries work well, and have enough sugar to freeze at a lower temp. Strawberries that have been frozen from the frigid atmosphere and rethawed have a changed consistency.
Kiwis are delicious, we think they will work through the skin, but we generally peel the whole thing and slice after carbonated. Cutting the endsoff might work as well, but it might take a bit longer.
We haven't tried a watermelon. Hole drilled into the thick rind (think trepanation) or a core removed from the longitudinal axis might facilitate impregnation of the "amusing" gas.
Some fruit seem to freeze easily, but still work well after thawed. Grapes, for example, appear to be pure enough water that the freezing temp is quite high, but they don't change too much and some people like frozen carbonated grapes, go figure.
Experiment with a test run. When I do this (most Minicons - Now Most CONvergences) I am not doing it for an "audience" and don't care how much I have or if it turns out perfectly (rarely). Find out what the consensus is on impressiveness, coolness, or other valued qualities this process imparts to various edible stuff in the opinion of the party throwers.
Cold seems to be part of the equation. Our best scientific estimate (and I have PHd'd physicist on staff who was one of the discoverers, never mind that he was an aspiring master at the time) is that the slowed molecular motion both aids in diffusion and in retention. Indeed removal from the CO2 atmosphere will eventually remove carbonation, as when letting soda go flat. Also, exposure to room-temp CO2, seems not to work either.
Advanced Carbonaters:
We haven't really played with this, but it may be that the optimum absorption occurs somewhere between the point at which the fruit would be frozen, and room temp. If this is the case, a well insulated cooler is a hinderance, since the CO2 sublimes more slowly. In order to maintain a vigorously refreshed CO2 atmosphere, providing a method for conducting away the cold (metal to metal contact with a big metal thing like the Air Conditioner units perhaps...) might leave enough cold around to optimally diffuse/infuse the CO2 while not freezing, and thus changing the texture, of the target goodies. I have no thoughts yet on what kind of container or conductor would be the best for this process. Hack away!
We also haven't tried Nitrous Oxide. That gas is just slightly heavier than CO2 (Nitrogen is one step up from Carbon) and it is fat-soluable (which is why it does what it does to humans with toothaches or at Grateful Dead concerts). Unfortunately, as amusing as this might be, getting this gas in a convenient cold form is next to impossible, it can be explosive (the oxygens are considerably more willing to leave), and the resulting effect is not what everyone is looking for. Merely a chemistry problem to unravel, like the rest of this treatise.
Good luck!