|
|
 Originally Posted by BananaStand
A chick just took me to a place that sells nitrogen ice cream. What did I just eat?
Ice cream.
Diatomic nitrogen, N2, is inert and composes more than 3/4 of the air we breath. Chemically, it's about as safe to work with as anything gets.
The Liquid Nitrogen (LN2) is used as a coolant and nothing more. It doesn't bond with anything in the ice cream, or change the food at all. It chills the cream and evaporates into normal air. (Note that it's air lacking all oxygen, and the N2 will sink to the floor, so asphyxiation warnings are due. Use it in a well-ventilated area, and you're fine.)
If done with skill, LN2 ice cream is a bit smoother and creamier than other ice creams, due to the rapid cooling making it less likely for ice chunks to form as it cools. Ice still forms, but not in macroscopic bits. You need to mix the cream rapidly while adding the LN2 to do this, and if mixing by hand, it probably wont be enough to get this effect.
We make it regularly in the physics department as a fun cap to a meeting. (Not faculty meetings, but anything involving new or prospective students, and any student group can make it whenever they like.)
LN2 is readily available in any large city. It's produced as a by-product of more desirable liquids, like liquid oxygen, which is used in welding. It is incredibly affordable, usually running less than $1 per liter (~$0.30 per L in St Louis). You need to provide your own container, and don't mess around with this. If you're not an experienced welder, don't even try to make one yourself. You'll want to buy a Dewar, which is a fancy name for a lab-quality thermos.
***
Our recipe:
1 qt half and half
2 Tbsp vanilla extract
1/2 cup sugar
Add any flavorings. For chocolate ice cream, add chocolate powder or syrup (~1/3 cup).
All quantities are rough guidelines, and personally, I think a bit of salt does a lot for the taste.
Mix ingredients and stir in a bowl. Slowly pour in the LN2 while stirring the liquid, and it will set into ice cream in a matter of seconds. If it starts to melt, just start stirring again and add a bit more LN2.
Using heavy cream instead of half and half will make a richer tasting ice cream, but some people don't want the added fat.
|
Reply With Quote