Monday, July 6, 2009

Keeping it cool

By now it's probably pretty obvious that I'm all about cheap, easy solutions to common brewing issues, and since currently I am just waiting around to taste these two screwed up beers I made from "home-malted" barley, I thought I would talk a little about regulation of fermentation temperatures. For me, living in Florida, that means cooling down the fermentation vessel, since I will never need to warm one up as long as I live here. Cooling is something that I need to consider every time I brew, except for maybe those 1 or 2 lucky batches that get brewed in the middle of winter.

Most of the year, we have central air conditioning that keeps our house at a steady 76 degrees, which is already at the high end of desirable temps for ales. But then you also have to take into account the fact that the fermentation process itself generates a small amount of heat, so at that point you end up with your ales being fermented in the high 70's or even over 80 degrees - not ideal. So I use the cooling effects of evaporation to keep my ales chill. All you have to do is wrap a moist towel around your carboy, and the evaporation will keep the beer anywhere from 5-8 degrees cooler than the surrounding air. You can even place a small fan next to the carboy and it should provide even more cooling - depending on the humidity in your house, even as much as 10-15 degrees! You can remove the towel every day and re-wet it, or you can just spray it down every so often - that's what I do:

When it comes to lagers, the only option I have is to ferment them in my regular fridge. If I turn the temperature control all the way up, my fridge stays between 49-51 degrees (a few degrees variation is pretty normal). This can be just a tad low for some yeast, but if you wait long enough it eventually attenuates. I always use a diacetyl rest, which means when the primary action is mostly over I remove the fermentor from the fridge and let it warm up to room temperature over the course of 24-48 hours. This re-activates the yeast and allows it to eat up diacetyl, a compound that is naturally produced during fermentation and tastes like butter - not a good flavor for most beers. After that, I lager the beer by putting it right inside my kegorator - it fits alongside the keg and CO2, and stays around 30-35 degrees (in this picture the CO2 is hidden behind the keg):

I know this may sound crazy, but the only lager fermentor I have that will fit in my fridge is an old 5-gallon kerosene can! I got it a long time ago when I had a salt-water fish tank. When I used to refill the tank with fresh water, the pet store would sell me the water in these plastic kerosene cans, so nothing has ever been inside there except for pH balanced salt water! I basically just drilled a hole in the top, and then inserted a rubber stopper and blow-tube. It fits perfectly on the bottom shelf, and is relatively easy to pull out:

So, even though I don't have any fancy cooling equipment, I still manage to keep my beers as close to ideal temperatures as possible without expending too much time or energy. That's what it's all about, right?

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