Fermentation temperatures

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hulkavitch

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I have read posts that say fermentation temperatures are 8-10 degrees higher than ambient. With that having been said if you are using a johnson controller/chest freezer combo, the probe is attached to the fermenter, and you want to ferment at 62.

Do you set the controller to 62 or 52?
 
8-10 seems a little too high. It could get that much higher than ambient, but probably only for a very active fermentation. One problem with setting to an adjusted ambient is that the heat generated by the yeast varies with time. Adjusting for the heat generation might be better than not doing it at all. But you would be better off using a thermowell or taping your thermocouple to your fermenter and setting to the intended temp. But if you don't want to do that, then yes, set temp to intended temp minus the heat you expect to be generated during fermentation. You could also initially set to the intended temp and once fermentation starts trim the temp back a few degrees.
 
asked a similar question recently. im thinkin you are gonna want to be around 52-54, for the initail fermentation and raise the temp a deg or two till you hit ideal wort fermentation temps.
 
Will taping the probe to the fermenter give acurate ferm temperatures? I thought it would be closer to ambient.
 
hulkavitch said:
Will taping the probe to the fermenter give acurate ferm temperatures? I thought it would be closer to ambient.

You should tape the probe to the fermenter with some paper towels or napkins in between the tape and the probe. This will insulate the probe and the temp in the fermenter.

The temp should be closer to the fermentation vessel rather than the ambient temp.

Also, i'm now using mostly stainless for my fermenters and makes the temp transfer a little better than glass or plastic.
 
Oh, and if I want to ferment at 62 after this insulation, I set it to 62.

If you're really concerned, get a thermowell
 
In my experience, the difference between ambient and ferm temp depends on the yeast. I mostly use US-05, and in that case it's only been a few degrees higher than ambient, but I've used S-04 and it was ridiculously higher, more like 8 degrees up!
 
Depends on the brew but for most I find I get 3-4 degrees above ambient when the temp is low. If the temp is higher then I see as much as 10 degrees over ambient.
 
I saved some bubble wrap. I tape the probe to the plastic fermenter and then tape a couple layers of bubble wrap over the top for insulation. The liquid crystal thermometer on the bucket matches the probe reading very closely. "Ambient" air temps in the freezer are all over the place.
 
I saved some bubble wrap. I tape the probe to the plastic fermenter and then tape a couple layers of bubble wrap over the top for insulation. The liquid crystal thermometer on the bucket matches the probe reading very closely. "Ambient" air temps in the freezer are all over the place.

This. My Johnson readout and crystal fermometer are usually spot on, or within 1ºF at worst. I've used bubble wrap to insulate but now I just use a large handful of balled up plastic grocery bags.
 
I initially used a thermowell but had some significant problems with the response lag (due to the thermal mass of the beer and central location of the thermowell) leading to overshoot. So what i do now is put the thermocouple against the carboy glass and cover that with a drywall wet-sanding spounge then tape that to the carboy. Any convenient good insulator will work though.
 
If you're really concerned, get a thermowell

Or you can make one. Revvy has a thread here on a really easy and cheap homemade thermowell (I believe he called it his "ghetto thermowell"). It works great, costs under $10 and takes about 30 mins to put together. I went that route instead of spending ~$30 at Midwest for virtually the same thing.
 
Just listened to a podcast that quoted an article in BYO were a guy did some testing with fermentation temperatures. He found that the difference of having a probe in a carboy (thermowell) and placing a well insulated probe on the outside of the bucket was less than .5 degrees difference.

So... forget about a thermowell im going with some tape and bubble wrap.
 
The issues with the thermowell overshoot and the success of the insulated probe on side method totally make sense. If the outer beer temps are at your ideal more than likely the center will reach thhat ideal eventually but if the center is at a certain temp it is likely that the edges of the batch are at colder temps and the ambient air is colder still...

In short thanks for convincing me not to get a thermowell and measure the side of the fermenter instead :D
 
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