What is this stuff?
Xanthan gum is a small microorganism called Xanthomonas campestris bacteria (its the good bacteria, people, not the bacteria that makes you sick) and is produced through the fermentation of glucose and sucrose (usually from corn).
How is it used in ice cream?
Xanthan gum is found in many foods and is often used as a stabilizer or emulsifier. In ice cream, xanthan gum stabilizes the air bubble structure and gives the ice cream a better texture and more creamy mouth feel. Xanthan gum also acts as an emulsifier and evenly distributes the fat molecules throughout the ice cream, giving it a smoother texture. This makes xanthan gum a great tool when you are attempting to make ice cream without egg yolks, which acts as the emulsifier in custard-style ice creams. Because air and fat are evenly distributed, xanthan gum also helps prevent the formation of ice crystals in the ice cream (but not completely; still not a good idea to leave the ice cream on the counter too long).
Is it used in other foods?
Xanthan gum is also found in other foods such as salad dressing and sauces. In this capacity, the xanthan gum helps prevent the oils from separating and suspends solid particles (such as spices). Xanthan gum also is frequently used in gluten free baking. Since wheat, and therefore gluten, are omitted from this type of baking, xanthan gum gives the dough the "stickiness" that gluten usually provides.
Are there any risks to using xanthan gum?
Some people complain that xanthan gum can have a laxative effect, but most sources note that this usually occurs at large doses. Since a little xanthan gum goes a long way (especially when making ice cream), I don't think many people will have a problem with the amount of xanthan gum in my recipes.
Where can I purchase xanthan gum?
You can usually find xanthan gum in natural food stores, or you can purchase it online. Bob's Red Mill is a good online source.
What if I don't want to use xanthan gum?
If you do not want to purchase or use xantham gum, you can always fall back on the Jeni's tried and true ice cream base and use cream cheese as a emulsifier substitute. Cream cheese will still help you achieve increased scoopability.