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Aquarium heater burn out in rum wash

PostPosted: Mon Dec 16, 2019 8:58 am
by JayTee
Hi - I've recently been trialling using a 300W aquarium heater (immersion) in the bottom third of my 250L rum fermentation. I bought a German-made titanium heater and controlled it via a separate probe and controller as I thought it would be more reliable. The first fermentation was great, but the heater failed on the second fermentation. It failed 3 days into the fermentation when the ferment was pretty much complete and the yeast was dropping out of suspension presumably. I found a 2 inch band of baked on yeast on the aquarium heater. Bummer. That didn't happen the first time. Don't know what I did differently.

Has anyone else experienced a similar issue with immersion heaters? I really don't know what I did wrong the second time, and I'm thinking I may have to move to a RIMS set up if I can't get the immersion approach to be reliable. Would appreciate any comments please! :-)

Re: Aquarium heater burn out in rum wash

PostPosted: Mon Dec 16, 2019 2:50 pm
by coffe addict
I've used aquarium heaters and found that they are quite reliable, the only difference is mine are usually toward the top 1/3.

Re: Aquarium heater burn out in rum wash

PostPosted: Mon Dec 16, 2019 7:43 pm
by Maxxx
I’ve had 2 x heaters in the last 4 years, both this “pet works” brand and both only 100 watt
Used in 200 litre ferments of both rum and vodka, always on the bottom of the fermenter, usually just tie the cord through the handle of a ceramic coffee cup to hold it down
The one that did break was only because I dropped it on the concrete.
Think they cost about S12 from the local aquarium supplies place and came with a 12months replacement guarantee

Re: Aquarium heater burn out in rum wash

PostPosted: Tue Dec 17, 2019 12:00 am
by JayTee
Thanks @coffe addict I think that might be the answer. I'm going to combine the top third placement of the heater with a circulation of the wash from bottom to top of the vessel for the whole fermentation.As this will keep the rum wash moving, I'm hoping this will keep the yeast from dropping out of suspension and busting my heater too ... :-)

Re: Aquarium heater burn out in rum wash

PostPosted: Tue Dec 17, 2019 6:30 am
by woodduck
I wouldn't over complicate it. I think it only stuck to it because it was sitting in the yeast bed. I would try lifting it up a bit first before making a recirculation system. Plenty of blokes use these heaters without a drama.

Good luck

Re: Aquarium heater burn out in rum wash

PostPosted: Tue Dec 17, 2019 6:36 am
by db1979
The wash moves all by itself from the rising and falling of yeast as they produce CO2 and rise, then release the CO2 and fall.

I've had one of those cheap aquarium heaters, I put a stainless hose clamp on the bottom of it to help weigh it down, worked well until it decided to die on me. I've also got a more expensive one (about $30) that doesn't need extra ballast and it's still working fine.

Although, I don't use them much here in Brisbane.

:text-+1: agree with woodduck

Re: Aquarium heater burn out in rum wash

PostPosted: Tue Dec 17, 2019 6:40 am
by db1979
Also, if your fermenter is well insulated (rubber mat base and wrapped in a blanket for example) it really doesn't matter if the heater is near the top. You just need to make sure that the heater is immersed properly, which is harder to do at the start of the ferment as the density of the wash is higher, it lowers as sugar gets converted and the heater is less inclined to float. Seems only a problem with the cheap ones.

Re: Aquarium heater burn out in rum wash

PostPosted: Tue Dec 17, 2019 12:52 pm
by EziTasting
db1979 wrote:...
I've had one of those cheap aquarium heaters, I put a stainless hose clamp on the bottom of it to help weigh it down, worked well until it decided to die on me.


I might need to have a go at this as mine constantly floats to the top... haven't used it because of it...

Re: Aquarium heater burn out in rum wash

PostPosted: Wed Dec 18, 2019 10:15 pm
by RC Al
What sort of controller was it, perhaps the heater didn't like it? SSR?

I would be inclined to trust the temp setting on a quality aquarium heater, just use a separate temp probe to double check and adjust the units own controller in future

Re: Aquarium heater burn out in rum wash

PostPosted: Thu Dec 19, 2019 9:11 am
by JayTee
Really appreciate all the helpful comments guys - thanks. I won't over-complicate it then. Woodduck is most probably right, it might have been in the yeast bed. I didn't have a floating issue with my one, but I'm guessing it's probably a bit heavier than some (titanium casing)

Re: Aquarium heater burn out in rum wash

PostPosted: Thu Dec 19, 2019 9:17 am
by JayTee
RC Al - just a basic temp controller with an attached probe. I bought from the same manufacturer as the titanium heater:
https://www.amazon.co.uk/dp/B01ERWPSXA/ ... 11_TE_item

I bought this heater:
https://www.amazon.co.uk/dp/B005UN48IC/ ... 11_TE_item

Re: Aquarium heater burn out in rum wash

PostPosted: Mon Dec 28, 2020 12:21 am
by OzDistilling
JayTee wrote:Hi - I've recently been trialling using a 300W aquarium heater (immersion) in the bottom third of my 250L rum fermentation. I bought a German-made titanium heater and controlled it via a separate probe and controller as I thought it would be more reliable. The first fermentation was great, but the heater failed on the second fermentation. It failed 3 days into the fermentation when the ferment was pretty much complete and the yeast was dropping out of suspension presumably. I found a 2 inch band of baked on yeast on the aquarium heater. Bummer. That didn't happen the first time. Don't know what I did differently.

Has anyone else experienced a similar issue with immersion heaters? I really don't know what I did wrong the second time, and I'm thinking I may have to move to a RIMS set up if I can't get the immersion approach to be reliable. Would appreciate any comments please! :-)


Generally aquarium heaters are not designed for constant operation. At best a 75% duty cycle. Using a smaller heater in a large volume of water, means the heater will be on constantly for maybe days initially to bring the temp up. They are just not designed to be on 100% for days on end. My advice. Buy 4 of a cheaper chinese brand and run them all from a external thermostat. Set all of their internal thermostats to max prior. This will reduce the initial warm up time by 4. Option 2, use a continuously rated heater, like a heat belt or pad.

Re: Aquarium heater burn out in rum wash

PostPosted: Mon Dec 28, 2020 6:55 am
by RC Al
Bit of a necro thread, but i realized that i missed a clue, and i could be wrong here but..

The burnt on crud says either
A. that part of the heater was out of the liquid. They are designed to be fully immersed, so it was tyring to heat your air in the fermenter as well and without the lipuid cooling the case... Pop!
Or
B. It was in contact with the yeast bed that caused a hot spot in the heater surface, the internal element would have melted there

Standard sizing of a tank heater is 2.5 to 5 watts per 4l depending on the ambient temp difference. If your fermenter is wrapped it should be at the lower end

I do agree that multiple small ones would be better to spread the heat more evenly, but most people seem to get by just fine with a single

Re: Aquarium heater burn out in rum wash

PostPosted: Mon Dec 28, 2020 7:08 am
by RC Al
Should have read some other replies first hey...

Lols