So I got a fun one.
I brew 20 gallons at a time and ferment in a converted temp controlled freezer containing four 6.5 gal. plastic carboys. I keep 2 on the top shelf and 2 on the bottom shelf, which is the only way that they'll fit in there. I've been noticing that the 2 carboys on the top shelf are on average 4 degrees warmer than the 2 carboys on the bottom shelf during fermentation. I'm assuming this is because the heat from the bottom carboys is rising. I keep the temperature probe taped to one of the carboys on the bottom because If I tape it to one on the top, The bottom gets so cold that the yeast in those carboys often shuts down or they don't attenuate well, leading to diacetyl. Meanwhile, the carboys on the top have more esters from the higher fermentation temps. I've never read of anyone having these issues but I'm sure I'm not the first. Seems like I'm between a rock and a hard place as either position of the probe leads to bad things. Any ideas? Right now my best solution is to tape the probe to the bottom fermentors and set the temperature at the lowest setting I can within the optimal temp range of what yeast I'm using. That way the top shelf will at least be within range, although higher than I would like.
I brew 20 gallons at a time and ferment in a converted temp controlled freezer containing four 6.5 gal. plastic carboys. I keep 2 on the top shelf and 2 on the bottom shelf, which is the only way that they'll fit in there. I've been noticing that the 2 carboys on the top shelf are on average 4 degrees warmer than the 2 carboys on the bottom shelf during fermentation. I'm assuming this is because the heat from the bottom carboys is rising. I keep the temperature probe taped to one of the carboys on the bottom because If I tape it to one on the top, The bottom gets so cold that the yeast in those carboys often shuts down or they don't attenuate well, leading to diacetyl. Meanwhile, the carboys on the top have more esters from the higher fermentation temps. I've never read of anyone having these issues but I'm sure I'm not the first. Seems like I'm between a rock and a hard place as either position of the probe leads to bad things. Any ideas? Right now my best solution is to tape the probe to the bottom fermentors and set the temperature at the lowest setting I can within the optimal temp range of what yeast I'm using. That way the top shelf will at least be within range, although higher than I would like.
