DIY- Aquarium Style Fermentation

Ok, I’m really excited to show you this one!

My unit has no- heating, cooling or storage space…

I searched for endless hours on fermentation control..

It seems the most common method for fermentation is using a fridge and heat belt/pad in tandom with a temperature contoller…..I don’t have a second fridge, nor the space for it. One day in my local brew shop (Peakhurst) I was talking to the salesperson about the struggle to find a cheaper option for fermentation temperature control, a customer on his way out overheard and said ” fish aquarium” and walked out the door. Boom!!

Now this setup is perfect in the cooler climate, yet to be tested in summer, but I have been advised it should be ok as long as its under 30 degrees or so, as water temperature is usually a few degrees cooler than ambient air temperature. My apologies to peolpe up north- you could add a water chiller, but thats spending some coin.

I’ve been using this setup for a month now, it keeps temperature to the degree!!..enough talking, let me show you how.

You’ll only need 4 things…and if you already have an esky will cost about $100…..$$$…..I know but i think it’s worth it. The other option $100 will only buy you the fridge, and this will keep temperature more effectively.

So youll need 4 main items-

1) ESKY- Mine is 40cm L x 25cm W x 30cm D- 26 litres. It’s a tight squeeze for two carboys, but easily fits one. So depending on how many carboys you want going that will give you some idea. If you haven’t got a spare esky DON’T you go buy a new one, get on Facebook sales or Gumtree, you should get a decent size for $10-$20.

2) DUCT TAPE- use a good quality waterproof or highly sticky one, Bunnings or a good hardware store around $5

Silicone is also great to use as an alternative.

3) AQUARIUM HEATER- You can pick up a glass one for$10-$20, the problem is they are extremely fragile, and not all have temperature control. I made the investment on this Aquael “Unbreakable” Heater for $50 , its kept temperature perfectly so far and kept up to it’s “unbreakable” title.

4) AQUARIUM PUMP- The pump will keep the temperature even throughout your fermentation vessel, and don’t worry about the fact you run it non stop, this Marine Water Pump will cost you around $3 a year to run…better that a fridge right? And quieter!

Its fairly simple to set up…

Work out how many and where you want your carboys and work around them….the pump dosent necessarily have to face the heater like mine, both the heater and pump although minimal for a fish tank are more than enough power for what you need. I only notice my heater on (red lights come on) very occasionally. The main thing is the heater should not be not touching your esky ( besides the holder of course) or your carboys. Duct tape both the heater and pump down well, avioding any of the actual heater or intakes of the pump, they both come with suction cups, but suction cups are no good with plastic. See below….

I obviouly added more duct tape after these picks, but hopefully you got the idea? Just make sure they’re taped down well so you only have to do it once. You could also do all this with silicone as you’ll see in my update below. Also in my update, placing a tile or something solid that won’t melt inbetween the Esky and heater is a good idea.

Duct tape the cords carefully up and then back down the outside of the esky so they are neat and safe. You’ll want to keep the esky covered somewhat so your carboys are away from light, and to keep the water free of dust, etc to increase the life of the pump. I just cut holes in the lid, but your solution may vary to your set up..

Just remember…only run the heater and pump when under water! Just turn off at the powerpoint if your taking carboys in or out as the water level will drop.

Submerge your carboys half to 3/4, as far as you can so they don’t float.

Now your good to go….no more checking the temp of your carboy every 2 minutes 👌

When I work out a cheap way to chill things out in the summer, I’ll update. 😊


The fermentation vessel has been going so well I decided to upgrade, didn’t cost me anything, plastic containers, foam,floor tile and plywood all free. Just for your information as you can see you can get away with using plastic containers, but I’ve used 2 and insulated with foam inbetween to add strength. I’ve also used a floor tile to seperate the heater from the plastic, and used silicone to attach the heater..Ive now got room for 4 carboys instead of 2.

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