April 7, 2014 by Prost Brewing
In the Medieval period, brewers did not have the knowledge nor the technology to differentiate between the two main families of yeast known formally as the ale and lager yeasts. Yeast was simply acquired from the air itself. Without pure single strains of yeasts, beer was made from a random milieu of these single-celled fungi, commonly including both ale and lager yeasts in the mix.
So what determined whether an ale or lager beer was produced? The surrounding environment dictated which yeast was actively fermenting the brew. In a warm and cozy setting, ale yeasts were alive and feasting, and in cooler environments it was the lager yeasts that were hard at work.
Thus, in the cold German winters there was nothing but lagers to be had. When summer brewing was outlawed in 1553 in an attempt to cut down on the occurrences of bacteria spoilage of beer that had put any warm-weather beer drinker at risk, the production of ales no longer had a place in the German brewing world. The new brewing schedule only allowed brewing during the cool parts of the year from St. Michael’s Day (Sept 29) to St. George’s Day (April 23) when lager yeasts were most active and ale yeasts had become dormant. Herein lies how lagers came to dominate the world of German beer!
Luckily for the modern-day German beer drinker, this schedule ultimately led to the refined German art of brewing cold-fermented lager beers today known and loved by beer drinkers the world round! To get a taste of what almost 500 hundred years of German brewers’ dedication to perfecting the lager has produced head down to Prost Brewing this week. Prost Brewing has the widest and most authentic selection of German lagers in the Mile High City, offering Denver-ites and visitors to Denver a true taste of what we here at Prost like to call “German pleasure.”