(Independent) - It’s the poetry of abundance that gets most people giddy at harvest time — the heaping bins of grapes, the culmination of months in the vineyard, the crush. But for me the real thrill comes in the days following, when tanks begin to gurgle and emit their fragrant fumes. At that moment, when the yeasts begin their microscopic celebration, the air vibrates with life. Fermentation is pure magic. Saccharomyces cereveciae, those invisible yet ever-present little microorganisms, perform a miraculous microbial transformation. They feast, consuming the sugars found in juice, and convert them to alcohol and carbon dioxide. Yeast is hard-partying, but it’s also surprisingly delicate, thriving only within specific environmental conditions. If temperatures are too high or too cool, or if the must is too acidic or alcoholic, they languish and die. And if they do so prior to converting all of the sugars, the result is a stuck fermentation and possible spoilage. Modern-day winemakers typically avoid this situation by adding commercial yeasts.