It's been just over nine months since I started my adventures in homebrewing, and here we are, eight 5-gallon batches into it. That's not too bad for new brewers, but I think my co-brewer Mark and I can do better. My New Years resolution this year was to (at least) double the number or batches brewed in the upcoming year. That's an ambitious undertaking for amateur brewers. Assuming twenty batches, we're looking at having to brew just about every three weeks this year, and we've already missed January and half of February.
Before we begin another round of brewing, Mark and I are taking some time out to analyze our results from last year. We did pretty well with our first year in zymurgy, and most of our beer was better than we expected. There's a flavor that has been consistent in most of them, though. It's hard to describe, and I lack the vocabulary to describe it, but it's what I've come to think of as the "homebrew flavor". While not unpleasant, this flavor has no place in good beer, and in order to take our product to the next level, we need to first isolate the cause, and then remove it.
At this point, our best guess is how we ferment the beer. We started our newfound hobby last May, just as temperatures were beginning to soar here in Durham, NC. As I live in an older house, the insulation isn't the greatest and temperatures in "the brewery" fluctuate more than is ideal for ale yeast. According to John Palmer and Jamil Zainasheff in their "Brew Strong" podcast, this fluctuation in temperature is worse for the yeast than even a temperature that might be higher than ideal.1
Papazian suggests that fermentation of ale yeast "...should be maintained at temperatures of 60-70 degrees F (16-21 C)...but are best started at 70 to 76 degrees F (21-24 C)."2 The use of the word "maintained" implies a stable temperature, at least within that range, but it's unclear just how much fluctuation is acceptable. Another source of confusion is the "best started at" temperature range. Common sense would suggest that a higher starting temperature would assist the yeast in getting a foothold right off the bat before dropping down to a lower temperature for the remainder of the fermentation process. However, Palmer and Zainasheff never suggest this process, making it unclear if the starting temperature should be the same as the rest of the fermentation.
Lucky for me and my mad scientist alter-ego, this lends itself perfectly to experimentation! Regardless of which option is better, Mark and I need to find some way to reduce the temperature fluctuation during fermentation. We both agree that a refrigerator would be the best option, but neither of us have the money (or in my case, the space) for a full fridge just for fermentation. Mark is intrigued by the idea of using the thermal mass of a cooler of water to regulate the temperature. He wants to try to submerge the fermenter in the water, leaving just the next and airlock exposed, and covering the cooler with insulation. We could then heat the water with an aquarium heater or cool it with ice, as needed.
I'm more enamored with the idea of trying to build a fermentation chiller like John Thornton's, essentially a home-built ice chest that circulates ice-cooled air in an insulated box when the temperature climbs above a certain temperature. I think I like this one more because it would pass the wife-test.
Mark's preferred method is definitely the cheaper alternative, and less labor intensive up-front. The fermentation chiller is probably less messy, though, and requires less effort to regulate on an on-going basis. There are definitely pros and cos to both. Whichever we end up doing, though, it will help us to experiment with more stable fermentation temperatures, and hopefully reduce or eliminate that mysterious flavor that has graced our home brewed beer for the last year. I will post an update as we get the results of our tests.
Fermentation temperature isn't the only change we need to make in our fermentation processes, but for true empirical study, we can only change one thing at a time. Keep an eye out for future posts testing the adjustment of fermentation time and processes!
Works Cited:
1. Zainasheff, Jamil, and John Palmer. "Brew Strong: Fermentation Temperature Control." Audio blog post. The Brewing Network. 13 July 2009. Web. 14 Feb. 2011. <http://www.thebrewingnetwork.com/shows/533>.
2. Papazian, Charlie. The Complete Joy of Homebrewing. 3rd ed. New York: Collins, 2003. 126-28 Print.
