How much hotter than ambient air does internal fermentation really get???

Palmer says up to 10 degrees hotter, but what exactly is a typical increase?

The ambient air in my closet (where Im fermenting) stays pretty consistantly between 66 and 68, but I'm wondering if this is too warm during the attenuative stage.

I know about the stick on thermometers, but I've heard that they're not always reliable, especially since I use a plastic primary.

10 is the upper limit, 0 is the lower.

A quick mathulation determines that 5 degrees is average. YMMV.

I have brewed mostly pale ales with Wyeast 1056, and have found as much as a 7-8 degree rise over ambient air temp for the first 4 days or so, then it cools off while the fermenting slows down. I currently have an Oberon clone using Wyeast 3724 in my primary in my 64* basement, and the Ale Pail has only reached a high of 67*

It varies, and has alot to do with type of yeast and air temp. I am using a fermometer and I am sure it doesn't reflect the true internal fermenting temp, just close I guess.

I am doing my primary in a glass carboy with a water bath at approximately 72F with towels wrapped around it and I am finding that my initial fermentation is 68F. My other fermentation (that is close to finished) is about 65F. So, I am assuming using my water bath and towels my fermentation temp is about 3F warmer than a close to finished fermentation.

When my ambient temp was about 72 - 74F, I used a 5 - 7F difference in plain air with the glass carboy. This is why I went with the water bath for my initial fermentation. Depending on how thick your plastic carboy/bucket is, you may end up with more insulation from your ambient air.

If my ambient air temp was between 66 - 68F, I would not have my water setup going right now, I would just go for it in ambient air... YMMV...

I have always used a refrigerator after my early brewing because I was frustrated with trying to keep temperatures where they should be. I use a Ranco controller to hold within 2 degrees of the set temperature. It all depends on how much you like having control over your brewing process and how much you like brewing. Generally the more fermentable sugars and the more yeast the higher the temperature goes.

If the OG is big and the yeast pitch is adequate, it's about 10F.

Here are pics from two batches in my fermentation fridge. The first one is a huge barleywine in active fermentation. The temp controller probe is attached to this batch to hold it at 68F.



This one is an amber that was fully finished fermenting so its temp is only subject to ambient temps.

I am brewing my first nut brown w a dry yeast call "Danstar Nottingham brewing yeast. ambient holds tight at 68. Noticed my primary is creeping up to 72 and bubbler smells like bananas after 3 days.
I will cool down the ferment to 68, but not sure if the esters have already made me a banana nut brown ale...

Bobby_M said:

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Looking like that bottle seen better days buddy. I have seen crevass (sp) less dramatic than that.

GilaMinumBeer said:

Looking like that bottle seen better days buddy. I have seen crevass (sp) less dramatic than that.

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I think that's the cord for his temperature sensor.

GilaMinumBeer said:

Looking like that bottle seen better days buddy. I have seen crevass (sp) less dramatic than that.

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I think that is a wire of some type, not a crack in his fermenter. But I could be wrong.

Bobby_M said:

If the OG is big and the yeast pitch is adequate, it's about 10F.

Here are pics from two batches in my fermentation fridge. The first one is a huge barleywine in active fermentation. The temp controller probe is attached to this batch to hold it at 68F.

Click to expand...

I would think it the probe wire

Yes, temp probe line. How would a crack that large in a better bottle hold the wort in? Silly.