Originally Posted by rexbanner
I had heard that fermenting temps could be 5-10 degrees higher than ambient air temps. Then I got a thermowell and used it on a 1.094 OG quad that fermented very vigorously...3 degrees above ambient temp. It's pretty negligible.
I've done the same, and found that in a warm place, my beer was more than 10 degrees warmer than ambient! I think it's important to monitor the temperature and make adjustments as needed, and the fermometer stuck on the outside is accurate within a degree or two.