August 8, 2014 by Prost Brewing
While yeast is just one brewing ingredient, its impact on creating the finest German style bier possible cannot be understated. To understand its importance in our operations at Prost Brewing, here’s a closer look at what constitutes yeast.
Yeast is a fungal species, of which there are nearly 50,000 identified. Out of that total amount of fungal species, about 500 are classified as yeast. Only a mere fraction of yeasts are considered to have commercial purposes. The best known yeast species used commercially is Saccharomyces cerevisiae. In addition to its use in brewing, it’s also used in winemaking, baking, and in aquariums. Saccharomyces cerevisiae is the microorganism that’s responsible for fermentation in ales, or top-fermented biers. Another important species in the same genus is Saccharomyces pastorianus, the yeast that’s used in lagerbier fermentation. One key difference between the two is that cerevisiae ferments at near room temperature, and pastorianus ferments at approximately 41 degrees Fahrenheit.
With so many known types of fungi in the world, it’s extremely critical that only the yeast appropriate for each bier style is introduced into fermenting wort. As we’ve discussed in previous posts, the yeast strain will determine the aroma, flavors, body, and appearance of the bier we produce. Think about the care and attention that goes into every batch the next time you’re enjoying an authentic German style Prost Brewing bier.