Different Types of Fermentations

Yeast belongs to the fungus group and is a single cell organism of the microscope. Yeast is found on soil, water, plant surfaces, and human skin. Like other fungi, yeast ingests food from surrounding organisms; they secrete enzymes that break down organic matter into absorptive nutrients. Yeast obtains food from fructose, glucose, and other monosaccharides (monosaccharides) contained in most fruits. Yeast enzymes chemically decompose sugars into products that cells can use.

Beer: Add yeast to malt cereal to promote fermentation producing alcohol. The type of yeast used affects the type and flavor of the beer produced. Saccharomyces cerevisiae also known as "top fermentation" or "top planting" yeast ferment at higher temperature and produce sweet or fruity beer. Bottom harvesters such as Saccharomyces pastorianus are fermented at lower temperatures and are used to make lagers. Wine: Yeast is naturally contained in the grape skin and can be used to ferment grape juice into wine. Despite naturally occurring yeasts, most wines today incorporate pure cultures (usually Saccharomyces cerevisiae) to produce more consistent and controlled results. Saccharomyces cerevisiae has various kinds of strains, each bringing unique flavor characteristics to the finished wine.

Yeast is a microorganism involved in beer fermentation. Yeast metabolizes the sugar extracted from the grain to produce alcohol and carbon dioxide, which turns the wort into beer. In addition to fermenting beer, yeast also affects its characteristics and flavor. The main yeast types used to make beer are the top fermented Saccharomyces cerevisiae and the bottom fermented Saccharomyces cerevisiae (Saccharomyces pastorianus). Brettanomyces fermented the Lambic and Torulaspora delbrueckii fermented the Bavarian weissbier. Fermentation includes wild yeast or airborne yeasts before understanding the role of yeast in fermentation. Several styles like Lambics today rely on this method, but most modern fermentation adds pure yeast culture.