Beer Forum

Right now I have a fridge for doing lagers in and I was wondering what method I should use for temp control. Control the ambient air temp or use a thermowell and control the wort temp? Or doesn't it really matter?

Tape the probe to the side of your fermenter, with a little bubble wrap over it insulating it from the air. Then the fridge will react to the beer temp, and you don't need to spend money on a thermowell.

Either Rock Candy or the Pope also cited several tests that compared the temps inside and outside the fermenter, for glass, ss, and plastic, and the differences were so small that it is the easiest and cheapest method.

HTH-

For lagering you only really need to control the ambient air. Since fermentation is complete the liquid and ambient air should be the same temperature.

I would def tape the temp probe to the side of the fermenting vessel covered with bubble wrap. This ensure two things:

1) During peak fermentation the fridge will react to heat produced in the fermenter. This will provide much better control because the ambient air will show less changes.

2) This will prevent the fermentation temp from lowering to much after peak fermentation is over. This will ensure that the beer will attenuate better and the yeast will clean up after themselves better. No body likes messy yeast.



As a heat sources in the fridge I just use a low wattage light bulb that is surrounded by cardboard so that the light doesn't skunk any of the beers. The light bulb provided enough heat to raise the fermentation temp from 68 F to 72 F after primary fermentation.

Yep, you definitely don't want to cool the ambient air. Ambient air heats and cools much faster than your wort. Thus it will cycle the compressor about 10 time more often, which leads to premature failure of the compressor.

Like BDawg said "Tape the probe to the side of your fermenter, with a little bubble wrap over it insulating it from the air. Then the fridge will react to the beer temp, and you don't need to spend money on a thermowell." That way when it does run you get longer run times and less starts, and face it, the ambient air will probably be about 5-10 different than the wort.

macgruffus wrote:For lagering you only really need to control the ambient air. Since fermentation is complete the liquid and ambient air should be the same temperature.

Excellent point, Macgruffus...however, I think that since this is in the fermentation section he means "Fermenting Lagers" instead of just "Lagering"...

andyp wrote:since this is in the fermentation section he means "Fermenting Lagers" instead of just "Lagering"...