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General Category => General Homebrew Discussion => Topic started by: grant on July 05, 2010, 05:16:00 pm

Title: Fermentation temp and hop bitterness
Post by: grant on July 05, 2010, 05:16:00 pm
I recently brewed an 11 gallon batch of double red ale using CL-50 yeast. I fermented half of the beer at around 68-70 degrees. The remaining half I fermented at 60-62 degrees in my fermentation fridge. The beer that fermented at 68 had a much more pronounced hop bitterness as compared to the half that fermented at a lower temp. ( SWMBO actually liked the second one because it wasnt near as bitter as the first.) I am wondering if the taste difference is due to maybe more malt flavor comming through because of the lower fermentation temp? Definately ended up with two good, but very different tasting beers.
Title: Re: Fermentation temp and hop bitterness
Post by: denny on July 05, 2010, 05:24:33 pm
Interesting question, Grant.  First, are you sure it's hop bitterness you're tasting  I'm trying to come up with some reason that a lower fermentation temp would accentuate malt and I just can't think of one.  Have you tried a triangle tasting to be sure?  Have your wife pour 2 glasses of one beer and one of the other without you knowing which is which.  Then try to pick out the one that's different.  That will help determine that you aren't imagining it.
Title: Re: Fermentation temp and hop bitterness
Post by: bonjour on July 05, 2010, 05:35:37 pm
AABG did an experiment with different yeasts,  differences resulted from using different yeasts (duh) and the amount of yeast in he beer at sampling (for the same yeast, same wort, different carboy)
Title: Re: Fermentation temp and hop bitterness
Post by: grant on July 05, 2010, 05:38:01 pm
The other thing I can think of is simply just the aging of the beer. The first keg that was fermented at 68 ,my wife wouldnt even drink it. She handed it back to me. Now after the second keg was tapped she is trying to drink the whole damn keg by herself because she likes it. The second keg was put into service about two months later. Maybe it is simply due to aging, and cold conditioning the beer longer. Dunno, and I wish I had some of the first keg left to do a side by side comparison
Title: Re: Fermentation temp and hop bitterness
Post by: bonjour on July 05, 2010, 05:40:13 pm
a couple weeks of additional aging brought the differences a lot closer together.

Title: Re: Fermentation temp and hop bitterness
Post by: grant on July 05, 2010, 05:42:33 pm
Well Fred, the amount of yeast was not the same pitched in each fermenter. I just picked up some from a local brewer friend, a couple of mason jars of CL-50. One had more in it for sure, but neither were lacking in the yeast dept.
Title: Re: Fermentation temp and hop bitterness
Post by: bonjour on July 05, 2010, 05:47:26 pm
Not the amount of yeast pitched, the amount of yeast remaining suspended in solution.  The experiment pitched a single vile of yeast into two different carboys with wort form a commercial brewery (2 tubes, 1 tube each) and fermented side by side.  Repeated for 20 different varieties of yeast.
Title: Re: Fermentation temp and hop bitterness
Post by: denny on July 05, 2010, 05:55:04 pm
The other thing I can think of is simply just the aging of the beer. The first keg that was fermented at 68 ,my wife wouldnt even drink it. She handed it back to me. Now after the second keg was tapped she is trying to drink the whole damn keg by herself because she likes it. The second keg was put into service about two months later. Maybe it is simply due to aging, and cold conditioning the beer longer. Dunno, and I wish I had some of the first keg left to do a side by side comparison

That might do it, Grant.  As as Fred mentioned, suspended yeast can impart a kind of bitterness.  CL-50 isn't always a fast flocculator, so the age difference may very well be what did it.
Title: Re: Fermentation temp and hop bitterness
Post by: babalu87 on July 05, 2010, 06:16:35 pm
Were both fermenters the same?

Carboy/Carboy
Bucket/Bucket
Carboy/bucket

Were the airlocks the same?
Title: Re: Fermentation temp and hop bitterness
Post by: grant on July 05, 2010, 06:31:14 pm
yes, both airlocks were the same, and so were the fermenters. 8 gallon buckets.
Title: Re: Fermentation temp and hop bitterness
Post by: babalu87 on July 05, 2010, 07:15:26 pm
Did the beer have a late hop addition?
Title: Re: Fermentation temp and hop bitterness
Post by: grant on July 05, 2010, 07:41:06 pm
yeah , here was my hop schedule

1.00 oz Columbus (Tomahawk) [16.80 %] (70 min) (First Wort Hop) Hops 26.3 IBU
1.00 oz Columbus (Tomahawk) [16.80 %] (30 min) Hops 17.8 IBU
1.00 oz Summit [15.50 %] (10 min) Hops 7.7 IBU
1.00 oz Summit [15.50 %] (5 min) Hops 4.3 IBU
1.00 oz Columbus (Tomahawk) [16.80 %] (2 min) Hops 2.0 IBU
1.00 oz Summit [15.50 %] (2 min) Hops 1.8 IBU
2.00 oz Summit [15.50 %] (0 min) Flameout