Xanthan gum is a polysaccharide derived from the bacterium Xanthomonas campetris. It is used to change the texture and viscosity of foods and liquids. Xanthan doesn't require heat to hydrate, and so it can also be used to alter cold liquids and sauces. It will also hold up during freezing, thawing, and microwaving, making it a versatile ingredient. Xanthan gum can be used for thickening, emulsifying, foaming, stabilizing, and suspending solids in liquids. A little bit of Xanthan goes a long way, so it is a very cost effective addition to your culinary bag of tricks.