Bob's Red Mill - Xanthan Gum, 226 g

Xanthan Gum is a plant-based thickening and stabilizing agent. It is named for the bacteria, Xanthomonas campestris, which plays a crucial role in this description. Technically speaking, xanthan gum is a polysaccharide, which is just a fancy way to say "a string of multiple sugars." To create xanthan gum, the Xanthomonas campestris bacterium is allowed to ferment on a sugar. The result is a gel that is then dried and milled to create the powder substance.
Xanthan gum has a number of powerful properties. First, it works as an emulsifier, encouraging liquids that normally don't like one another to mix together. Second, it works as thickener, increasing the viscosity of liquids and batters. Third, it can create a creamy texture.
In the world of gluten-free baking, xanthan gum plays the crucial role of imitating gluten. In baking, gluten is what makes dough "doughy." It gives the dough elasticity, as well as viscosity. Those properties help to hold a cookie together while it bakes on a sheet in the oven, and they enable cakes and breads to hold onto the gas bubbles that form inside them - this allows them to rise and take shape. Xanthan gum helps replicate these properties in recipes that do not contain gluten.