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Brewing Lager Beer
If you’ve mastered brewing ales, it's time to take things to the next level with a lager. These beers require a few additional steps during the mash and fermentation processes - impeccable cleaning and sanitation, precise temperature control, and a lot more patience to name a few. If you’re game for the challenge of making a lager, read on!
While most European lagers use two-row Pilsner malt, many massed produced American lagers historically used six-row barley combined with adjuncts like corn and rice. To some extent, this is still true. In general, lagers are lighter beers and lighter grains will be used. Though, there are some excellent one-off dark lagers out there in the world of beers. New Belgium Brewing Company’s 1554 is an excellent “Black Lager.” Also, the Dunkel style is comprised entirely of dark lagers.
Because lager beers use lighter malts (and less hops, which we explain below) the overall flavor is much more subtle than say, a stout or an IPA. This means that defects have nowhere to “hide.” If you’re cleaning and sanitation isn’t up to snuff and the beer has even the slightest hint of off-flavor, it will be easy to detect. More flavorful beers are often easier to brew because slight defects often go unnoticed under the mask of a heavy hop profile.
Lager beers aren’t typically very hop forward beers. They’re lightly bitter and only slightly hoppy, for the most part. In fact, the world of hoppy lagers is largely unexplored in the commercial beer world, which is a perfect opportunity for homebrewers. The ability and freedom to experiment with new styles is part of what makes homebrewing so much fun!
Some hops are definitely used in the production of american lagers, for example. Cluster and Hallertau seem to show up in a lot of these recipes. Though, you can pretty much use any standard, non-fancy, hop in these beers if you want to stick to the middle of the road (which we don’t actually encourage).
If you’re If you’re looking for a simple lager beer to begin with, here’s an excellent Pre-Prohibition Lager recipe.
The mashing process for lagers differs slightly, but significantly, from the process for making an ale. The most important additional step when brewing light lagers is making sure that mash pH falls within the suggested range. The second consideration may include the addition of a protein rest.
Because lager beers tend to be some of the lightest, the malt bill sometimes lacks the acidity to drop mash pH down into the 5.2 to 5.6 range. This will be especially true if the water you’re using has high bicarbonate levels, making it more resistant to pH change. Cutting bicarbonate rich water with reverse osmosis (filtered) water or even reducing the pH with lactic acid may be necessary.
Conversely, if you’re brewing a dark lager and are using water with low alkalinity, you may need to ADD some bicarbonate to hit pH targets! Check out our brewing water chemistry article for more information on this topic.
A protein rest is sometimes called for when brewing light lagers, especially when using 6-row grain, which has higher protein content than 2-row. A protein rest is generally conducted by mashing at 122F for 20 minutes before moving up to the standard mash temp range (140-160). This will activate specific enzymes that break down protein chains, reducing the haze or cloudiness of the final beer.
The most significant difference between lagers and ales is the yeast. Lager yeast ferments at lower temperatures than ale yeast, which results in longer fermentation times. More on this below. It also means that you may need to pitch more yeast for a healthy fermentation.
The best advice we can give when it comes to pitching yeast is to follow the directions on the package of yeast you’re using. For example, White Labs suggests pitching 2 packages of yeast if pitching into wort that has been cooled to primary lager fermentation temps, 55F for example. Another strategy they recommend is pitching lager yeast at about 68F. Once fermentation begins (when CO2 starts bubbling out of the air lock) drop the temperature by 10 degrees Fahrenheit every 12 hours until the desired fermentation temp has been reached. Yet another option is making a yeast starter a day in advance if you’d rather not buy an additional package of yeast.
Like ale yeast, lager yeast benefit from wort aeration, so don’t forget to vigorously shake the wort in your fermenter for at least 90 seconds before adding the yeast.
To ferment a lager, you’re going to need to be able to keep things cool, like 50-55 F (10-13 C) degrees cool. That’s cooler than room temperature but warmer than a typical refrigerator – so you’ll potentially need some specialized equipment to pull it off. The method we suggest (if you have the space) is picking up an old chest freezer and regulating temperature with an external temperature controller.
Once the yeast has been pitched and the wort has stabilized at primary fermentation temperature, expect it to take 1-3 weeks before primary fermentation is “done.” By done we mean, once the beer is about 2 points away from the target gravity. Once you hit this mark, move on to the diacetyl rest.
Conducting A Diacetyl Rest
A natural byproduct of yeast fermentation is a compound called diacetyl, which can result in a buttery or butterscotch-candy flavor in the finished beer that is generally undesirable. It’s typically removed by yeast, but the colder temperatures used in lager fermentation mean that the yeast are less active and also less effective at removing the diacetyl. There’s a workaround though.
Warming the fermenter to 65 degrees F for about 48 hours will give yeast the boost it needs to scrub diacetyl from the beer. Once finished, you’ll be ready to cold condition.
Aging Lager Beer
Once fermentation and the diacetyl rest has been completed, it is time to rack to a new vessel and complete secondary fermentation as well as lagering. We suggest racking to a keg (assuming you’ll be serving beer from a kegerator) and completing secondary and lagering it without transferring into a new vessel. All beer is sensitive to oxygen and we prefer racking only once during the process to reduce exposure. This will cause the first few pints will be very cloudy, and the dregs will get sucked out of the keg first, but with a bit of time it will clear up nicely.
According to Wyeast, secondary should be completed at about 40F for 1-3 weeks and lagering should take place at about 33 degrees for 10 to 30 days. But extending the lagering phase further can sometimes improve the beer. Some beers, such as strong German doppelbocks, are lagered six months or longer.
Bottling Lager Beer
Once your beer has been properly lagered, it can be racked to bottles, if you don’t have or want to use a keg. As always, rack the beer gently using a siphon and consider purging vessels with CO2 to eliminate oxygen pickup. Also, if the beer has a relatively high original gravity, 1.070 or higher, you may need to pitch some additional yeast, along with priming sugar, to ensure proper carbonation. A neutral ale strain can even be used to do the job.
Refrigeration of lagers is recommended but not required for long-term storage. But like all beers, it’s best to avoid exposing it to warm temperatures and direct light.