Belt heaters on class carboys

[DBuzard]

Hey I'm a novice Brewer. I'm on my second batch of beer and it winter. My basement is bout 50°f. I had just bought a belt heater and was wondering if I could use it on my glass carboy?

 

[Smellyglove]

I don't see any reason why you couldn't. Belt heaters are a popular choice.

 

[DBuzard]

Thank you. The directions say not to but I didn't know if it was just a suggestion or there was a reason behind it.

 

[Smellyglove]

That's only what I myself believe.. What instructions? And why not?

 

[fermentinginpa]

I have never used a brew belt before so I am not speaking from personal experience. I have read that they shouldn't be put on a glass carboy. From what I understand the temp fluctuation could cause it to crack/break. I do know someone that uses one and he uses it on glass but he doesn't let the brew belt touch the glass, he bunches up old towels and puts that between the belt and the glass. He swears by it but don't know how much that mitigates the risk (or how much risk there actually is).

 

[Smellyglove]

But you have 5(?) gallons of wort which will absorb the heat?

 

[DBuzard]

Yes I do.

 

[stosh]

I have a heater on a carboy right now that's been on for a few weeks already. Everything's still intact.

 

[stosh]

i also have one on my 1 gallon glass kombucha container

 

[parrothead64]

I’ve used it on a glass carboy for a couple of years with no problems. There is some chance the glass could break. You might want to move it to a warmer area. I never did it below mid 60 ambient

 

[MaxStout]

It might be the mfr. being extra cautious. It seems unlikely to create enough thermal shock to crack or break a glass carboy...but I won't go so far as to say it couldn't happen. Glass carboys can be touchy sometimes. The brew belt is intended for plastic vessels. Use with glass at your own risk.

There is a heater, the FermWrap, that is designed for glass vessels. Its heating element is a large sheet that spreads the heat over a much greater area.

 

[Keepcalm]

I have been using one since mid December. On my 3rd batch. Each time the belt has been on the carboy for about 2 weeks.

Though to add the ambient temperature for where I ferment is only a few degrees below from where I want to be.

 

[cegan09]

The warning comes from glass not being a great thermal transmitter. If you have untempered glass, with a large heat sink of liquid inside keeping the inner layers cool, then a strong heater on the outside, you'll create stresses in the glass which could cause cracking. That's the general theory, and it's why you don't boil yeast starter wort in cheap unknown flasks directly on the stove. With carboys i'm sure there is a huge range of quality between different sources, so some are safer than others.

However I would say the risk with a heating belt is rather low, since the heat applied isn't at a huge temp delta to what is inside the carboy. If you're worried at all the towel idea between the belt and carboy is a good way to spread the heat more and prevent a violent thermal shock. Or used one of the heaters made for glass as mentioned above.

 

[ThatITGuy]

I've never used a Brewbelt before, is there automatic temp control on them?

 

[Smellyglove]

I've never used a Brewbelt before, is there automatic temp control on them?

Some has, but that's nothing you'd want to use. A thermostat controlling the belt is the way to go.