Yeast

Yeast is a miscellaneous item in the Fallout 3 add-on Point Lookout and Fallout: New Vegas.

Background
Yeast is a fungal microorganism used in the baking of bread and distilling of alcohol. When yeast ferments, it produces carbon dioxide gas and alcohols, making it a staple in the production the two.

Yeast
Yeast, in both games, is used in producing moonshine. In Point Lookout, it's commonplace to find it in houses, storefronts and on swampfolk. It's much more difficult to find in the Mojave.