Control Fermentation temp with Aquarium Heater

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chemist308

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This question is for those who control fermentation temps with an aquarium heater. Do you put in anything to ensure some circulation of the water bath you use?
 
I stir mine around every now and then. I use a probe thermometer to check the temp of the water bath at least a couple times a day and it seems to stay pretty constant.
 
I don't really stir it. I guess it would be better to do that, but it seems like the water bath and the fermenter temp are pretty constant and pretty close throughout.
 
This question is for those who control fermentation temps with an aquarium heater. Do you put in anything to ensure some circulation of the water bath you use?

I use a hydor Koralia aquarium circulation pump. Cheap, fully submersible and very effective. Without that, my water bath would be hot near the heater and cold at the sensor. Maybe my outer container is too tight for the carboy. With the circulation pump, temps are very stable.
 
I don't bother. The fermometer reads a steady 70 so I don't worry about it. I use a mop bucket on wheels, so it's a pretty close fit and there isn't that much water anyway.
 
There's no need for a pump with such a small volume. The volume of water is low enough that the entire volume will reach equilibrium quickly; thermal mass will help stabilize the temperature once it reaches your indicated temperature.
 
I recently noticed that there's a big difference between the top and bottom layers
of water.
I have a 100W aquarium heater in a big round tub.
With an Ale Pail inside, 5 gal water is about 8 inches deep.
Near the bottom the temp is 67F.
The temp rises with height until it's 72F at the top.
I also would have thought that it would reach a more uniform temperature.
The basement is about 56F this time of year.
I may have to switch to some kind of cooler.
 
Not to Hi-jack this thread, but today I bought a 100W aquarium heater for keeping my beer in the basement warm. My basement can get down to about 58 or so I don't need alot of warming but just 10 degrees or so. I bought an adjustable heater so I can lock in at a temp.

Anyways I would like to be able to keep 2 carboy's warm in at the same time but can't seem to find a cooler big enough to fit 2 at once without spending a fortune. I've been looking alot online but most places only give you the outside diamensions and not the inside. I figure I will need about 26" long by 13 or 14 " wide. I know I could just use a big rubbermaid but I like the idea of also using the cooler in the summer to keep beer cooler.

Any suggestion?
 
Anyways I would like to be able to keep 2 carboy's warm in at the same time but can't seem to find a cooler big enough to fit 2 at once without spending a fortune. I've been looking alot online but most places only give you the outside diamensions and not the inside. I figure I will need about 26" long by 13 or 14 " wide. I know I could just use a big rubbermaid but I like the idea of also using the cooler in the summer to keep beer cooler.
They make them that big -- I wish I knew the model or make of this one, but it has no markings that are revealing.

fermenter.jpg
 
They work great. I check mine with 2 thermoters and check all corners and all around for that matter and the temp difference is never more than .5 between the top and bottom and sides. It also keeps the water the same temp.

It is great temperature control. I even drapped a sleeping back around it to insulate it a little more.

P1040722.JPG
 
[bump]

Just found this thread after setting up a water bath and aquarium heater. It holds the temp perfectly, but I have my digital thermometer taped to one spot, so I wonder if the water is circulating enough. I tend to agree with another poster here that there's so little water to circulate that it will equilibrate on its own pretty quickly. I think there's maybe 2-3 gals of water in the tub. Is a pump really needed?
 
I use a large fish tank wrapped with R-19 household insulation. It has two 6.5gal acid carboys sitting in it at the moment, fermenting.
I use a 100W fish tank heater (element without thermostat), mini fish tank pump, and a Ranco controller.
It will hold 68 even when it's 40 in the garage.
 
[bump]

Just found this thread after setting up a water bath and aquarium heater. It holds the temp perfectly, but I have my digital thermometer taped to one spot, so I wonder if the water is circulating enough. I tend to agree with another poster here that there's so little water to circulate that it will equilibrate on its own pretty quickly. I think there's maybe 2-3 gals of water in the tub. Is a pump really needed?

I just started a batch yesterday and what I found is that the top of the cooler is about 10 degrees warmer than the bottom. This morning the top was 70F while the bottom was 60F. My setup is a 60qt Igloo with a 150W heater, the temp in the garage is ~45F, the cooler has at least 5 gallons of water in it. Last night I put a piece of foam insulation on top of the cooler but that didn't help to equalize the temp.

I will be getting a pump today.
 
Rubbermaid Roughneck 31 gal (#2244)

I nest 2 of them now as the picture shows the walls bowing quite a bit when full. I was worried about a fracture at some point. The aquarium heater is visible in the 1st pix and the pond pump for circulation in the 2nd. I use a Ranco controller for the heater as at it's coolest setting kept the tub at 70F. The probe wire is visible going between the 2 Better Bottles but what isn't seen is the thermowell. The stock probe is not waterproof. In the warmer months I add a little bleach to the water to keep the algae at bay.
DSC000291.JPG
DSC000303.JPG
 
I just started a batch yesterday and what I found is that the top of the cooler is about 10 degrees warmer than the bottom. This morning the top was 70F while the bottom was 60F. My setup is a 60qt Igloo with a 150W heater, the temp in the garage is ~45F, the cooler has at least 5 gallons of water in it. Last night I put a piece of foam insulation on top of the cooler but that didn't help to equalize the temp.

I will be getting a pump today.

When I got home today the fermentation was more active and the temps stabilized a bit on their own. There was only a 3 to 4 degree difference. Since I picked up the pump on the way home I put it in and the temps stabilized in a couple of minutes.

I think the active fermentation has a lot to do with the temps being more stable. Once that is gone they will probably diverge again.

I got the smallest submersible pump I could find at Petsmart. It was in the reptile section and has a flow rate of 45gph. http://www.petsmart.com/product/index.jsp?productId=2752547
 
rcrabb22 - how well does that aquarium heater work? How much can it go above ambient temperature?
 
rcrabb22 - how well does that aquarium heater work? How much can it go above ambient temperature?

As long as the target temp isn't much higher than the ambient (5 to 8 degrees), I think the aquarium heater worked great. I used the heater with a small pump and had great success.

I got tired of hauling water and dealing with the water bath. And, I was just estimating what the internal temp was and adjusting the temp of the bath. So, I finally picked up a 2-stage temp probe, thermowell, small fridge and ferm wrap to maintain temp. More $$ but now I am dialed in and hands free. I'd recommend getting fermentation temp control dialed in 7 days a week and twice on Sunday - far ahead of just about anything else in the brewing process (cleaning and sanitization is first, IMHO).

Good luck.

JBrew
 
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