With half of our fruit already fermenting, the smell of yeast permeates the winery and the caves. Our output of thousands of bottles is the work of billions and billions of these little creatures. In fact, next to the grapes, yeast are the single most important ingredient to making wine. Yeast choices affect the flavor, aroma, texture, and body of the wine. During fermentations, we coddle them by cooling or warming tanks to match their preferred temperature, and winemakers constantly experiment with new and different strains while also relying heavily on their old favorites to get the job done.

Eventually, the success of a yeast colony becomes its own demise. Yeast are intolerant of high heat and elevated alcohol solutions, yet they produce both through their fermenting abilities. And, once the wine goes dry and there are no sugars left, the yeast lose their primary food source, causing them to die off, producing what we call the lees.