Braden Neihart [+]
Necessary for fermentation, yeast is a microscopic fungus that surrounds us and grows on all matter of organic material. They float through the air and facilitate fermentation. Saison and farmhouse ales are the most notable styles that rely on yeast terroir; they are open fermented and let local yeasts that clings to walls of the brewers to fall in. This is many ways where we will see terroir the most as yeast is a local product. It can be cultured and imported, but quickly takes on new characteristics.