Lagers used to be cold stored in underground cellars and caverns.

One of the basic divisions in beer is between ale and lager. Ales, of course, are fermented near room temperature with species of yeast that prefers warmer temperatures. Lagers are fermented cooler (9-12 degress Celsius) with yeast evolved to prefer that temperature. This most of us know. We also know that the slower ferment in lagers creates a smoother, cleaner taste, while ale yeasts produce more esters.

But there is another piece to the lager puzzle that doesn’t get as much attention – lagering. “Lager” is German for storage, or warehousing, so to “lager” is to store the beer for a period of time. More specifically to store it at cold temperatures (as close to zero as is practical). Most of the time lagers undergo a 2 week to 6 month period of lagering before being packaged. Historically, that was in deep caverns under the brewery. Today breweries set aside conditioning tanks, or possibly a room, for this process.

The purpose of lagering is to continue the clarification process and to allow certain compounds, like sulphur, dead yeast, protein chains and other less desirable components to drop out of solution. It makes the beer brighter, cleaner and smoother.

For homebrewers and small craft brewers alike, lagering is a fairly intensive process requiring both extra time and extra equipment (especially at the homebrew level). Thus many homebrewers and smaller craft breweries don’t do lagers and stick with ales. Others brew lager-styles but skimp on the lagering periiod (a common homebrewer cut corner). Still others, like myself, make do with a less than perfect lagering period. My set up will only get me to 8-10 degrees Celsius, but I can hold it there for 4-6 weeks fairly easily.

The science behind lagering is clear. But can people really taste a difference? That may be for each person to decide, but I worked it out (for myself) a few years ago. When doing up my annual lager, following the diacetyl rest (a short period when the beer is increased to room temperature to complete consumption of diacetyl chains), I proceeded with my lagering, but pulled a couple of bottles out right away. When the rest of the batch was ready, I tried them alongside the lagered version. For me the taste difference was substantial – even with my less than ideal lagering temperatures. The lagered version was cleaner and seemed less complex (in a good way). I was convinced.

I raise this today because I recently had a bottle of Pilsner from a craft brewery (whom I choose not to name). I know from an interview with them in the past that they don’t lager their pilsner – an issue of capacity and equipment. This is a fair choice and the beer is very good – hence I feel no need to out them.

I enjoy the beer, great hopping regime and a crisp pilsner malt sweetness. But what I noticed was that the beer came across more like a hoppy blonde ale than a pilsner. Hiding in the background was a subtle fruitiness and a bit of sharp yeast notes. Trust me, it was subtle. Had I been drinking this beer cold, fresh from the tap line, I likely wouldn’t have even noticed. But in my glass it was  a bit warmer and some of those complexities started to be released.

I was struck that this was likely the result of not lagering. A well-made beer, with quality ingredients and clearly a deft touch. It just lacked that final crispness that, I believe, can only be achieved through at least a couple of weeks of cold aging prior to bottling. It reminded me of the questions upstart homebrewers have about the “necessity” of lagering.

This beer addresses the complexity of answering that question. No, it is not “necessary”. You can make a great tasting lager without a period of cold storage. However, lagering does accomplish something. It will subtly alter and shape the beer and make it more “lager-like” (if I can be obtuse). For homebrewers (and small craft brewers), not lagering is a viable option if equipment or time are an issue. But something, however subtle, will be lost. But we all make compromises at various times – this is just one of them.