How to automatically controlling fermentation temps?

[bbrally]

I want to use a fridge to control the temps in my carboys, but I'm curious how to control the temps without having to keep adjusting the thermostats.

As the yeast get active and start producing heat, the fridge temp needs to be turned down to keep the heat in check. But as fermentation progresses and the yeast slow down, the fridge will have to be turned back up to keep the temps from getting too cold.

What can be done to automate this adjustment?

If I stick a thermowell in the carboy and cycle the fridge based on the carboy temps, it seems the temps would swing quite a bit as there would be a lot of lag in the system.

Would using a two-stage heating/cooling system improve that lag? Running the fridge till target temp is reached and then running a heater in the fridge to prevent temps from coasting too far below the set value.

 

[Darwin18]

Buy a temperature controller. The digital one on northern brewers site is literally plug and play. I have two - one for the keezer and the other for the fermentation freezer and they work great.

 

[Pratzie]

Do a search for STC-1000. Build urself oneof those and make a cheap heating element or buy a small space heater. That will cover all your questions and concerns as long as u program the variant and the delay correctly.

The main thing is, don't leave the temp prob just loose in the air, insulate it against the side of the carboy if u aren't going to use a thermowell inside the fermentor. that will prevent the temp swings.

 

[slow_boat]

Put your digital temp probe in a jar of water, and then note how much it overshoots. You can adjust your lower bound until it hits your target. I run this setup on two freezers, one for primary, and one to lager.

 

[bbrally]

I was having trouble finding info on how people were doing this until I searched STC-1000, then lots of solutions popped up. Thanks for pointing me in the right direction.

I'm thinking of using my BCS-462 to control the fridge/heater. Perhaps cool the fridge till the beer target temp is reached and then turn off the fridge and turn on the heater to bring the ambient air up to the beer target temp. When the beer temp starts to rise again, turn back on the fridge and repeat. There's probably enough thermal mass in the carboy to prevent too much cycling of the fridge.

 

[day_trippr]

Using the heater is a bit silly if you have a BCS. Use two probes, one solidly thermo-coupled to the fermentation vessel, the other hanging in free air. Use the first to set the process target termination temperature, use the second to govern how cold you let the chiller get...

Cheers!