By Christopher Jennings
Summer is upon us. It is the time of barbecues, the sun being up for 12 hours, and crisp, refreshing home-brewed lagers. Making lagers doesn’t have to be reserved for the cold frigid winter, especially since in the winter our fermentors are filled with stouts, porters, and barley wines. As with their ale counterparts, there are many different types of lagers; some that we want to drink now and others that will be great in the colder months.
Unlike ales, lager yeasts prefer colder temperatures for fermentation. The best temperatures are below 60F and above 45F. Maintaining a constant temperature is very crucial as well. If you can keep the ambient air temperature in a room around 55F, then you have a perfect lagering chamber. If you can’t control a room’s temperature, the next option is to control the temperature of individual fermentors. You’ll want to use glass carboys for this because the glass allows for a much easier transfer of heat. Before you start controlling the temperature of the carboy you should add a strip thermometer to the carboy so that you have a more accurate reading of the internal temperature of the wort. Also remember lager yeast is a bottom fermenting yeast so you may not see any activity on the top of your fermentor. However, it will still off-gas CO2 but at a much lower rate because the colder the wort is, the more CO2 it absorbs.
Keeping it Cool
We now have our fermentor equipped with a temperature meter of some kind. The next piece is a pan or shallow container that will hold your carboy and have a little room to spare. Once everything is in a relatively stable environment, watch your temperatures. If your wort is too warm, add cold water to the pan. If in a few hours the temp has dropped enough, you want to wrap the carboy in a wet towel. Every day you are going to need to check to make sure your towel isn’t dry or the water is too warm, or the carboy has gotten hot. This seems like a lot of work just for some nice crisp lager but in August it is going to be well worth the effort.
Post Fermentation Treatment
Your lager may take a few extra days to ferment out than most of your tasty ale recipes. Just like ale yeast you may have some diacetyl in your finished product. To avoid this, allow the carboy to warm up to room temperature on the last couple of days of fermentation. This will allow the yeast to clean up all those off flavors. The next step is to bottle or keg as you would normally. The only difference is, once your bottles have carbonated at room temperature, the lagering stage is to put your bottles at cellar temperature or in your cooler allowing it to “brighten” or “crisp.” If you are kegging the best thing is to allot some space in your kegerator and have the keg hooked up to pouring pressure. This will let your beer slowly absorb CO2 and lager at the same time. This process can take as long or as short as you decide. Only you can choose how long you think your tasty homebrew needs. Once it is ready, the flavor should be that of the crisp and refreshing hot summer day beer we all know and love.
Download the recipes:
Grass Clipper (AG)
Grass Clipper (Extract)
Stories from the print edition of the Oregon Beer Growler.