Brewing Lager Beer
By Jim Busch (Brewing Techniques)
Part I: An Overview of the Lager Beer Brewing Process
Patience is required to master the complex process of lagering, but U.S. home brewers are embracing the technology to brew lagers every bit as clean and delicate as those of Europe.
This installment of Home Brewery Advancement begins a two-part series on some of the important processes required to lagering. This issue, I summarize the process of lager brewing. In the next issue, I will explore the chemistry and art of the lagering process.
A Long and Delicate Process
Lagers are very different from ales in recipe formulation, brewhouse processes, and the all-important temperature-controlled fermentation and lagering. Lagers are much less forgiving than ales because they are delicate, clean, and balanced. Fruity esters, hot higher alcohols, and the huge bittering levels often found in ales are usually avoided in lagers.
Good lagers are hard to find in the United States, and until recently it was rare to find many home brewers who understood the subtleties of lager brewing. This situation is changing as craft brewers become more capable of producing world-class lagers and the home brewing community becomes more technically oriented. This series explores how to successfully brew great lagers at home.
Most first-time brewers focus on ales; only after one becomes fairly experienced does the extra effort involved in brewing lagers seem reasonable. Lagers are more complex and take more time to prepare. The lagering process occurs over weeks and only after the completion of primary fermentation. Lagers also require higher pitching quantities of yeast than do ales, and the choice of yeast strain is at least as important as it is for ales. Brewhouse procedures that minimize oxygen pickup are even more important for pale lagers than for ales. In addition, careful temperature control during the fermentation and lagering periods is essential. For all of these reasons, lagers are hard to make well and are best reserved for more experienced brewers.
Some definitions: The German word lager literally means “to store.” Practically, it defines a style of beer that is fermented by S. uvarum (or S. carlsbergensis, after the historic research performed on lagers at Carlsberg Brewery in Denmark). Lager yeasts are often termed “bottom-fermenting,” but this is misleading because S. uvarum does not ferment on the bottom (nor does ale yeast ferment on the top). Instead, the yeast tends to flocculate (drop from suspension) toward the bottom of the fermentor (and with ale yeasts toward the top) as the beer consumes the fermentable sugars. Lager yeasts ferment some complex sugars that ale yeasts cannot.
Lagering is the process by which lager beer is aged for extended periods at cold temperatures. Strictly speaking, lagering occurs after the completion of fermentation. In unitanks, primary fermentation yeast is dropped and discarded at the conclusion of primary fermentation. In most home brewing conditions, the beer is racked off the primary yeast and allowed to lager in a separate vessel such as a Cornelius keg or a closed carboy. Six weeks is a typical lagering period for a traditional Pils-gravity beer (12–13 °P); 12 weeks or more is typical for a 20 °P Doppelbock.
Click here to browse our selection of Lager recipe kits to brew your own at home!
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