Brewing lager beer is an art driven by processes, particularly the processes of fermentation and maturation. Fermentation is widely acknowledged to be the main point of difference between lagers and ales. The common wisdom goes something like this: ale yeasts ferment faster and warmer, are top fermenting, and are more flavorful compared to the slow, cold, bottom-fermenting and neutral-flavored lager yeasts. This presentation discusses the various types of lager fermentations, the variables to consider when fermenting, and the “lagering” or maturation process.

Notoriously, the German Reinheitsgebot laws mandated that only water, hops, malt and yeast could be used in the production of beer. Thus, a lesser-known side effect of the so-called “purity law” was that modern brewers had to develop methods for natural carbonation that could be scaled up to full industrial scale production. Two of these methods, krausening and spunding, are the continuation of lager fermentation and greatly influence the flavor.

Learning Objectives:

• Review the three types of lager fermentations: traditional cold fermentation, modern hybrid fermentation, and warm lager fermentation
• Address fermentation variables, repitching, and lagering and how these variables are related to the type of fermentation methods performed
• Finish with spunding and krausening to show how natural carbonation is possible with lagering