Fermentation Exothermic? If so how much?

Ok, Brewed yesterday, everything is happy happy (no bubbles yet but looking good).

So my next thoughts are temp related.

To manage temp, I have read here that some use water bath's, Fish bowl heaters, Ice in water.... all to manage temp. Then there are those who just put in the crawl space and rely on natural temp control.

So I'm thinking it's an exothermic reaction but don't know how much. So this morning I put a thermometer in water in the same location to track temp, but that will not account for any exothermic reaction.

So how much of a rise in temp do you see over ambient in a 5.5 gal pail of wort/yeast?

Currently I'm maintaining 61.3 deg.

I've seen as much as 8°F above ambient in a very active fermenter.

Yuri_Rage said:

I've seen as much as 8°F above ambient in a very active fermenter.

Click to expand...

+1. Some strains just go gang-busters.

If you take some small pieces of bubble wrap and use several layers as insulation to tape a thermometer to the outside of the fermenter, you can get a pretty good approximation of the fermentation temperature.

The degree of difference between ambient temp and fermentation temp is usually anywhere between a "few" degrees to 10 °F or more, but it depends on many variables (yeast strain, how vigorous the fermentation is, fermentation point-in-time, thermal mass of fermenter, etc). So, it's difficult to calculate a number of degrees.

Also, the fermentation temp you're shooting for depends on yeast strain and what you want in the final beer (flavor-active compounds). Generally, cleaner beers ferment on the lower and of the yeast's optimal fermentation temp range and more "flavorful" beers ferment on the higher end.

Ok. so how active is S-04?? Which is what I used.

Should I get ready to control temp? and how do you measure your wort/yeast temps inside the bucket?

The instructions say 66-68 deg, I'm thinking 61.3 room temp should hold it under 68 given the above replies but I like to be prepared if needed.

Thanks to this site for the great info, sure made yesterday go a lot easier than i thought it would go! Even with my newbie errors.
Can't wait for the next brew day!.... I may need to head to the LHBS and get another primary... and order a 2nd or 3rd keg... =)

S-04's "recommended" fermentation temp. range is 15-24°C (59-75°F), so you're fine where you are, but may end up with a slightly "cleaner" beer. It will still be good, though. I love S-04.

Thanks! I guess S-04 is the perfect yeast for a newbie... =)

So if I understand you correctly, (within the yeast range) lower temps create cleaner beer tastes, Higher create more complex tastes.

I guess I'll have to brew lots of beers and record the results and tastes for each to gain the knowledge I need to make the beer I like.

I would like to make Seattle Mac & Jack, it's the best beer I've ever had.

I usually keep the ambient temp 5°F below my desired fermentation temp.

Thanks Yuri,
That's a nice rule of thumb.

last check, my thermo (In water) is up to 63.5 F. now so adding 5 to that gets me to 68.5.. just over the recommended but I like a beer with some substance.
I'll continue to track temps as I'm not driving 60 miles to get a new thermo to attach to the primary today. I'll have to get one for the next beer though. (remember to put on list... )

Just put an LCD thermometer on your primary if you want to see the temp. I've got a strip on every bucket/pail/carboy/etc that I own.

My barleywine hit 11F over ambient at the 48 hour mark.