Reinzuchthefen

Reinzuchthefen, or pure culture yeast, is a category of baker's yeast produced by isolating a single strain of Saccharomyces cerevisiae and maintaining it in a pure culture. The aim is to ensure the absence of other microorganisms, providing more consistent fermentation and leavening characteristics.

Production and forms are controlled by yeast suppliers, who maintain a master stock of a selected strain and propagate it under sterile conditions to produce commercially sold fresh, compressed yeast or dried forms. The term reinzucht distinguishes it from mixed or wild strains that can occur in spontaneous fermentations or in less controlled products.

Historically, the concept originated in the late 19th century with the development of pure culture methods by microbiologists such as Emil Christian Hansen. These techniques led to standardized baker's yeast and enabled industrial-scale baking by reducing variability caused by contaminants and mixed strains.

Uses and advantages include leavening bread dough with predictable performance and aroma. The quality and behavior of reinzuchthefen depend on storage and handling: fresh forms require refrigeration and have a shorter shelf life, while dried forms store longer and are more shelf-stable. As with all yeast products, storage conditions, expiration dates, and proper rehydration or activation influence results in baking.