Homebrewing Blog and Resource

Fermentation Temperature Triangle Test

Its easy to brew one thing and call it done. However I am always eager to learn what I can about my brewing process to improve my beer or at least my knowledge base of beer brewing. On a recent batch of Brown Ale I split the batch into two carboys. I fermented one at ambient temperatures around 65F. The second carboy got wrapped with a brew belt and fermented closer to 75F. This week I put John to the test with a fermentation temperature triangle test.

I wasn’t sure what to expect about this little experiment. Admittedly, I was more interesting in seeing how a few ingredient and recipe tweaks would change my brown ale recipe. My gut as a home brewer tells me that if you ferment a beer warmer than its yeast range suggests you’ll get flavors that aren’t what you expect. Namely a warm ferment should increase esters for sure at best and at worst create some higher fusel alcohols and perhaps lead to a medicinal flavor. Perhaps too a warmer ferment could stress yeast sufficiently to get some premature yeast death.

I put John to the test and I wasn’t not surprised when he couldn’t separate the beers in a fermentation temperature triangle test. Not surprised because I couldn’t do it either. I was surprised however at the results of the tasting test; I could perceive no difference between the two samples.

Both samples have the same great caramel and toasted malt notes. There is a comforting bready/biscuit character as well. All things I love about the Brown Ale style. I don’t have a lot of experience with Wyeast 1028 London Ale specifically, but I am sure I’ve brewed with its White Labs equivalent WLP013. Both yeasts are solid English yeasts that flocculat well and give a great English Ale yeast character.

So why can’t we tell them apart? I have seen similar failings on the Brülosophy web site. so I took a little comfort in that. But I am still perplexed based on my ‘conventional’ homebrew wisdom about fermentation temperatures. I think what’s happening here is that perhaps the recipe and yeast choice is to blame. English Ale yeast already brings esters to the party. And the beer itself was designed to be pretty amped up as far as flavor profile goes. Are these aspects masking a subtle temperature effect? A future experiment with say WLP001 in my cream ale might be in order soon enough.

Have you experienced the same issue? Have you tried side by side temperature controlled ferments?
Let us know in the comments below.



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  1. Very interesting. I wonder how much of it is due to inconsistent temps rather than too high of temps.

  2. That’s a good question to be answered by another experiment.

  3. Todd

    You said “English Ale yeast already brings esters to the party,” but your tasting mentioned only caramel, toasted malt, bread, biscuits. Did you actually taste any esters? I’ve never used an English yeast other than WLP002, but I haven’t experienced it to be overly ester-y. Could be that when used with crystal malts you just don’t notice them. Or I suck at detecting them (though I do taste a slight riesling character with WLP029). I’ve never done just pale 2-row with a non-fruity hop and 002 to find out for sure. I’ve been curious about that for awhile, but reluctant to try because to me pale 2-row by itself is kind of bland.
    The brown ale sounds tasty.

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