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Old 02-05-2010, 02:53 AM   #1
LarryC's Avatar
Jun 2009
San Diego, CA
Posts: 728
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I have 5 gallons of AHS California Common Ale in primary and it is bubbling away. I used the recommended yeast, White Labs WL810 and I have a question or two.White Labs calls this a lager yeast but the temperature range is pretty wide 58 to 65 with a note saying it can go down to 50. The instructions from AHS said to pitch at 70 which I did and held it there until fermentation started - about 12 hours. I then added an ice bottle to my cooler that the carboy sits in and dropped the temp down to about 58.

With the cooler weather and the ice bottles I can keep things pretty cool but I am wondering about temperature fluctuation. I listened to a Brew Strong Pod Cast on fermentation and they say you need to hold the temp within 1 or 2 degrees or you can stress out the yeast. I'm probably getting more like 5 or 6 (58 - 63) degrees of variation with my ice bottle technique.

Is precise temp control during fermentation that critical? I thought as long as I kept it towards the low end of the yeast's range I was OK. Not so???

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Old 02-05-2010, 03:39 AM   #2
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ajf's Avatar
Oct 2005
Long Island
Posts: 4,646
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I've made hundreds of good beers without carefully controlling the fermentation temperatures, but I've also made hundreds of beers that could have been better.
I now carefully control my fermentation temperatures, and have found that the ratio of good to not so good beers has increased dramatically.

There are only 10 types of people in this world. Those that understand binary, and those that don't.

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Old 02-05-2010, 03:40 AM   #3
Dec 2008
Yankee Hill, CA
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It is ideal to keep your temps as constant as possible, but a lot of times it's easier said than done without a good fermentation chamber. As long as you stay in the given range you should be ok, but most importantly don't let it get too hot. That's much worse than a little too cool, IMO. I'm willing to bet the actual temps inside your fermentor are more stable than you think.
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