I know we've discussed this topic, maybe ad nauseum, in the past but new information has come to light for me.
I ferment all my beers including lagers in swamp coolers and have always been pleased with the results. Maybe that's all that matters but...
My stick on fermometers are getting kind of old and hard to read so recently I've been using the thermapen to check the swamp cooler water temp and just figure the beer in the bucket is within a couple degrees of that. This morning I decided to check the beer since I was going to pop the lid to see if krauesen was building anyway.
Swamp water was 52 degrees. Perfect lager ferment temp right? Well, I sanitized my thermapen and checked the beer in both buckets...62! WT!!
In the past I think we've generally agreed that there could be as much as a 5 degree swing in temp from the fermometer to the inside of the fermenter but 10 degrees?
If I go back to the second line of this post...."always been happy with the results..." Yea but...but...