Fermentation Temperature Control Concerns

[JoeNavy]

Haven't posted in here in a while, but I have a new concern.

I have never had the need for a heating element in my fermenting fridge, as the unit has been kept inside. After moving, I made a dedicated brewing space in an outdoor shed, but the temperature drops to the 50's at night, and my fermenter doesn't hold temps once the first few days of vigorous fermentation are over. I want to add a heating element, but my issue with that is my location of the temperature probe, and the location of the heat source.

I am currently using the submerged temperature probe (the thermowell), so it measures the temperature of the middle of the brew. I am planning on getting a heat jacket or heating pad. My concern is that the jacket will get too hot, and affect the outer layer of brew before the correct temp registers in my temp control unit. I have the same concern with the heating pad below the carboy.

Can someone who has experience with this ease my mind or concerns? Or, will the brief moment of overheat exposure to the outside layer of brew be negligible in the long run?

Thanks!

 

[aprichman]

I use a chest freezer and an STC-1000 clone for my chamber, the freezer is plugged into the cooling outlet and a fermwrap is plugged into the heating outlet. The fermwrap isn't touching the carboy, it just sits in the chamber.

Temp probe is hooked up to the outside of the carboy, insulated with a couple layers of bubble wrap taped over the probe.

This keeps my carboy within ~+/- 1°F of the set temp.

 

[JoeNavy]

I use a chest freezer and an STC-1000 clone for my chamber, the freezer is plugged into the cooling outlet and a fermwrap is plugged into the heating outlet. The fermwrap isn't touching the carboy, it just sits in the chamber.

Temp probe is hooked up to the outside of the carboy, insulated with a couple layers of bubble wrap taped over the probe.

This keeps my carboy within ~+/- 1°F of the set temp.

Thanks for the input, however, I am looking to see if wrapping the carboy or putting the heat source directly on the carboy has an affect on the brew in terms of thermodynamics. I would love to do a similar setup to yours, but I use a wine fridge and don't have that kind of space.

 

[GoeHaarden]

They're designed to be placed directly around the fermentor. It's a gentle heat, so I doubt you will get much temperature variation within your carboy. A lot of people use them without issue...

 

[orionol73]

I also ferment in a wine fridge and use this for my heat source. I have it velcro'd to the side wall of the fridge

https://www.amazon.com/dp/B00DOZGLYM/?tag=skimlinks_replacement-20

 

[aprichman]

The flexwraps/fermwrap probably run around 90°F. I was originally going to wrap it like you are planning but putting something that warm directly on my carboy just felt wrong.

 

[Hwk-I-St8]

I use a heat belt and just put it directly on the fermenter. Never really thought about heat stratification other than I always put it near the bottom (since heat rises).

During active fermentation, there's a lot going on, so I don't worry about the wort not mixing much. With all that CO2 being created, I imagine it keeps the wort moving around and mixed pretty well.

After the really active stuff, I'm not as worried about it getting a little warmer.

 

[Ninoid]

Depend of yeast type. Some are sensitive to temperature changes (S-04) and some are not (US-05, S-34/70).

 

[JoeNavy]

I use a heat belt and just put it directly on the fermenter. Never really thought about heat stratification other than I always put it near the bottom (since heat rises).

During active fermentation, there's a lot going on, so I don't worry about the wort not mixing much. With all that CO2 being created, I imagine it keeps the wort moving around and mixed pretty well.

After the really active stuff, I'm not as worried about it getting a little warmer.

That's a good point. I usually bump it up to 72-73 degrees anyhow after active fermentation. I'll try it out, and trust that it's a mild enough heat not to reach that 80+ (which I highly doubt anyway) range.

 

[Kealia]

I used a wrap on carboy when I was using carboys and now have it on my SS BrewTech fermentor with a probe in the middle of the unit that extends into the middle of the wort.

I've never had an issue, nor a reason to worry about it.

 

[day_trippr]

Regardless of the style of heater, don't make the mistake of overkill as it will make control much more difficult than a properly sized device.
Eg: a hair dryer in a minifridge or 5cf chest freezer is right out
A commercial fridge in 50 ambient isn't going to need a lot of heat to maintain fermentation temperature. I run 40W heat sources in two 17cf ferm fridges in my essentially unheated basement where 55°F isn't unusual in the cold months and they get along just fine...

Cheers!

 

[JoeNavy]

I ended up getting a small heater wired to an InkBird to go in my shed. It keeps ambient to 70 at night, so I don't have to worry about low temperatures anymore. Thanks for the input!