Fermenting temp in Fridge

[SWEadamNZ]

Hi.

I ferment my beers in a temp controlled fridge, and if I want to ferment at 18C I usually put the controller at 18C. But I know the ambient temp is not the same temp as fermenting temp. But would that be the same when I ferment in a fridge? I got a thermometer strip on the bucket which says 18C as well.

So should I just leave it like that or bring it down a few degrees?

Cheers
Adam

 

[lumpher]

what i usually do is start it at 18c, then leave it alone, but i do leave my heat sensor connected to my bucket

 

[soccerdad]

Others here know better than I. In my experience ambient will be at or close to beer temp, EXCEPT when fermentation is most vigorous. At that point, and for roughly 40 to 70 hours, the beer temp will be somewhere between 4 and 8 degrees warmer than the ambient temp.

 

[brewbama]

The ambient air temp and fermenting wort temp can be very different. I recommend you tape the temp probe to the fermenter and cover it with insulation. A couple layers of bubble wrapped taped over the temp probe should do it. That way it is reading the sideway of the fermenter and not the air.

 

[alhounos]

Most will recommend insulating the probe against the fermentor, since the fermenting beer will be warmer than ambient.
However, I'm lazy, so I just use a 1L jar of water as a thermowell in my fridge. If I want a beer to ferment at 18C internal, I set the controller to 16C. Close enough for me. I have measured the beer during active fermentation and it has been just about on the money.

Of course after the first 48-72 hours, fermentation will slow, and the internal temp will fall, so I raise the controller temp to my desired internal temp (say, 18C). After 5-7 days it's out of the fridge at ambient to finish up.