Wild Yeast Fermentation

Wild or native yeasts, according to a general definition, occur naturally in the air or on surfaces. While the word, ‘wild’ might give the romantic impression that winemaking’s native yeasts come from the grapes in the vineyard, it’s just as likely a wild ferment is the result of yeast from winery equipment or even the floor. Commercial yeasts, on the other hand, are cultured in laboratories and turned into powders or liquid cultures. Winemakers can select a particular commercial yeast strain from dozens of options in catalogues (see chart on pg. 36). When they want fermentation to start, they simply add the yeast to the must either by sprinkling it into the must, or by adding water to rehydrate the yeast culture and pitching it into their juice – a process called inoculation. With a wild ferment, on the other hand it’s a bit like magic: You crush the grapes and just wait until fermentation happens. Wild Versus Commercial A simple analogy might help explain the difference between commercial and wild yeast fermentations. Picture two suitors: A successful accountant and