- micro-organism, fungus
Fungus that reproduce and convert available sugars into alcohol. Wild yeasts are found naturally in the vineyards and readily available on the grapes, and are known as the spontaneous yeasts. The yeasts used for wine production belong to the yeast species Saccharomyces cerevisiae. Yeast strains, or cultured yeasts, are very popular for vinification, and are available in a powder form.