Temperature control in Primary question

[joshyG]

Hey so I have carboy in the mini fridge with a temperature controller and it just started bubbling 4 days ago. The carboy has one of those stickers on the side to read the temperature, but when I set the temperature controller to 47 it reads on the carboy that its like 55 or 54?

So then I put a bottle of water in the fridge and let it sit overnight and that ready 50 degrees. So that is confusing.

What do i trust the side of the carboy or the water?

Thanks,

Josh

 

[user 246304]

You're seeing the heat generated by your yeast in growth. It's common absent a glycol jacket or something like that for your ambient to be as low as 10 deg. below the temp in your fermentor.

 

[Qhrumphf]

Fermenter stickers are commonly relatively accurate. Fermentation produces heat. This is why an cool room often isn't good enough.

Your best method will be installing a thermowell in your fermenter and using that for your temp controller so the fridge compressor is tied to the beer temp, not the air around it.

 

[Upthewazzu]

Get a thermowell like this one and you should be pretty spot on: https://www.amazon.com/gp/product/B01KP4D0K2/?tag=skimlinks_replacement-20

 

[Qhrumphf]

Just make sure whatever thermowell you choose will fit your temp controller's probe. They're not universal.

 

[RM-MN]

Hey so I have carboy in the mini fridge with a temperature controller and it just started bubbling 4 days ago. The carboy has one of those stickers on the side to read the temperature, but when I set the temperature controller to 47 it reads on the carboy that its like 55 or 54?

So then I put a bottle of water in the fridge and let it sit overnight and that ready 50 degrees. So that is confusing.

What do i trust the side of the carboy or the water?

Thanks,

Josh

Where do you have the probe for the temperature controller? It needs to be affixed to the carboy and covered with some kind of insulation so the controller knows what temperature the beer is. Unless you have a bad controller it should be able to keep the beer at the temp it is set for.

 

[joshyG]

Nice that has to be it.

I never realized the fermentation caused heat, but that makes sense.. given the fluctuation from the water to the sticker on their carboy to the temp I set it too.

Thank you guys!

Cheers

Josh