/ 20 g yeast

Yeast refers to unicellular fungi, most commonly Saccharomyces cerevisiae, that perform fermentation by converting sugars into alcohol and carbon dioxide. Culinary yeast is a living organism harvested and processed from brewing or baking strains, available in various forms depending on moisture content and processing method. The cells are dormant when dried and activate upon rehydration with warmth and food sources. Yeast strains vary in fermentation speed, alcohol tolerance, and flavor compounds produced, with baker's yeast (Saccharomyces cerevisiae) being the primary variety used in bread production and home fermentation.

Nutritionally, yeast is rich in B vitamins, particularly thiamine and niacin, and contains all essential amino acids, making it a complete protein source when consumed in larger quantities. Its flavor profile ranges from neutral (baker's yeast) to complex and fruity, depending on the strain and fermentation conditions.

Yeast is essential in bread baking, where it produces gas that leavens dough and develops flavor through fermentation. Active dry yeast and instant yeast are the primary forms used in home baking, contributing rise time of 1-3 hours depending on temperature and recipe. Beyond baking, yeast ferments beverages (beer, wine), preserves vegetables (sauerkraut, kimchi), and creates starter cultures for sourdough breads. Fresh yeast (cake yeast) is preferred by some professionals for its predictable fermentation rate, while dried forms offer convenience and longer shelf life. Temperature control is critical: temperatures below 50°F (10°C) slow fermentation, while above 110°F (43°C) can kill yeast cells.