How to measure ACTUAL fermentation temp?

[brokebucket]

Maybe you misunderstood me. I do insulate, but only the probe and about 3" in every direction from the probe. Am using stc to cause refrigerator to cool ambient when the insulated probe shows temp out of bounds. So I don't want to insulate the beer from ambient...else how would the refrigerator cool it... Am afraid if you insulate the fermentor in this situation you are asking for a runaway heat spike as the exothemic fermentation increases temp, accelerating fermentation, adding more heat....

Now if you can put some sort of chiller under your insulation, great, but then why would you even bother with the fridge?

I dont know who is more right, but I insulate the whole thing and do not have temp spikes. But if you need to raise temps, how do you do that?

 

[eric19312]

I dont know who is more right, but I insulate the whole thing and do not have temp spikes. But if you need to raise temps, how do you do that?

40W light bulb in the fermentation fridge. Had no issues in garage that got down to about 40 this winter. That's the beauty if the STC controller, it controls both the heater (light bulb) and the chiller (fridge coil).

Downside is I am only controlling temp of one fermenter. The other fermentor is sort of riding along. I always put the probe on the fresh batch as I think most of the potential damage from lack of control is in the first week when active fermentation is underway.

 

[balrog]

I have a little cube dorm fridge to cool, a little Lasko personal heater to heat, a 12v PC fan on a cellphone wall wort to circulate the air around a little stacked up 2" rigid foam board "chamber" with STC flashed with AlphaOmega's STC-1000+ firmware for °F and temp profile ramping. I set it to 1°F and during active ferm first few days I see the fridge cycling maybe 1.5 times per hour, 15 mins, to keep 63° in an ambient cellar 67° environment.

So it works great now. But will I be able to lager with this setup during the summer when cellar temp is 70 and I want to hold 50? Dunno. I've actually seen a thread somewhere on here where someone showed the dQ/dT calculation given 5G thermal mass and BTU fridge output but I just can't recall it.

I do remember reading that the temperature critical first few days of active fermentation is also during time when the yeast activity is roiling and boiling that wort, mixing it (and edge to center temps) quite well. Anytime other than that, you likely aren't trying to move temps very fast through that big 5G thermal mass anyway.