Aquarium water heat

[Nomofett]

Hi,
I have my fermenter surrounded by water in a bucket with an aquarium heater with adjustable temp. and I'm not sure what the water temp should be. I know the beer temp is supposed to be at 70-ish and that inside the fermenter the fermentation process can add 10-15 degrees to the ambient heat. So I assumed that 55-60 is good, but then I was reading about how water conducts heat and how it pulls heat out of whatever is in it and that's why water feels colder than air at the same temp.

So my question is: if my water heat is 60 will the fermentation process still raise the heat inside? Or will the water be so good at conducting that it will even it out to the same temp as the water.

I'm brewing one gallon batches and my fermenter is glass.

Thanks!

 

[emclinux]

I don't have an answer for your question. But this is a great idea. Are you using this for 1 gal or 5 gal fermenters?

 

[Nomofett]

My fermenter is a little over 2 gallons and I have have one gallon fermenting in it. The bucket is big enough to fit 3 fermenters (my order is coming in the mail tomorrow to do the other two)
This is my first time brewing but I read about the aquarium idea on these boards and thought it was a great idea and I think it'll work great. Today it was snowing and in the area I live in houses are built for hot summers and not cold winters (Osaka, Japan) so the walls are super thin. It was freezing where I have my fermenter but the set up kept everything going along. I also toss a blanket over it.
View attachment ImageUploadedByHome Brew1420174946.229399.jpg

 

[Singletrack]

One gallon is not going to be 10 to 15 degrees warmer than the surrounding water -- maybe a few degrees. Probably you want to ferment less than 70 degrees, depending on the yeast. I suggest heating the surrounding water to 62 to 65 degrees. You can raise up to 70 after fermentation slows in 2 to 3 days.

 

[Nomofett]

So the surrounding water and the fermenting beer should be about the same temp?

Thanks!

 

[davehuge]

I'd think that, given you have a glass (which conducts heat pretty well) fermenter and only a small amount of fermenting wort, the temperature differential won't be large. 65 F is a good temperature for ales so the previous suggestion of 62-65 for the water is a good one. As said before, you can raise the temp after 3-4 days as fermentation starts to slow down.

 

[Nomofett]

Thanks!

 

[eadavis80]

I also use an aquarium heater - in fact, what looks to be the same one you have, though maybe not because the lowest my heater allows is 68. I also am brewing 5 gallon batches in PLASTIC BUCKETS, so there are a few big differences in our processes. I will say this: 1) I only use the heater during the 2nd week in primary. My room is about 63-65 for the first week of fermentation. I know that fermentation can add several degrees, so I keep it out of my water setup as I don't want to ferment in the mid 70's. Secondly, I have noticed in my setup at least that the temperature of my beer is actually COOLER than what my fermentor thermometer reads. When I took a gravity sample, I also took its temp. My thermometer on my fermenter read about 68-70, but the temp of my wort sample, according to my liquid thermometer, which I trust, read about 66. Now, glass might allow for more heat transfer than my plastic bucket does. But, in short, I'd keep it out of the water for at least 5 days after pitching and I might expect the beer in your jug to be a degree or two cooler than what your thermometer reads.

 

[Nomofett]

That's lots of good info, thanks! And we might have the same one, mine starts at 68 also. I just mentioned the other number because it's what I heard. In the spring I'll be able to keep it out but my apartment is super cold if I don't have the heat on, so at night and when I'm at work it gets freezing. There is one possible place I might be able to put it, I'll check the temp when I'm gone for a full day coming up soon. I live in a tiny apartment so it's hard to find any space for anything except for a little nook by my entryway.
Anyways, thanks for the advice!

 

[RM-MN]

I also use an aquarium heater - in fact, what looks to be the same one you have, though maybe not because the lowest my heater allows is 68. I also am brewing 5 gallon batches in PLASTIC BUCKETS, so there are a few big differences in our processes. I will say this: 1) I only use the heater during the 2nd week in primary. My room is about 63-65 for the first week of fermentation. I know that fermentation can add several degrees, so I keep it out of my water setup as I don't want to ferment in the mid 70's. Secondly, I have noticed in my setup at least that the temperature of my beer is actually COOLER than what my fermentor thermometer reads. When I took a gravity sample, I also took its temp. My thermometer on my fermenter read about 68-70, but the temp of my wort sample, according to my liquid thermometer, which I trust, read about 66. Now, glass might allow for more heat transfer than my plastic bucket does. But, in short, I'd keep it out of the water for at least 5 days after pitching and I might expect the beer in your jug to be a degree or two cooler than what your thermometer reads.

Put your beer in the water bath without the heater for the initial 3 to 5 days as that will moderate the temperature of the fermenting beer and keep it cooler than it would in just air. Once the ferment slows you should bump the temperature up with the aquarium heater, perhaps to as high as the low 70's as this will help the yeast with the cleanup.

 

[eadavis80]

I will do that when I only have one beer in the primary at a time, but recently I've had two primary buckets simultaneously, so I have one in my bedroom that's in the low/mid 60's and the other one - a week ahead of the bedroom batch - in the aquarium water tub. Sunday I'll only have one primary going as I brew my chocolate stout on Sunday and will be racking (yes, I rack, forgive me anti-rack people) my Irish Red to secondary and it will then be out of the aquarium bath.

 

[Merleti]

I would highly recommend you use an accurate thermometer to do additional test on the water temperature. Most aquarium heater I have found are not totally accurate. Also adding a small pump to circulate the water will help keep the temperature consistant with higher room temperature swings.

 

[WoodlandBrew]

Hi,
I have my fermenter surrounded by water in a bucket with an aquarium heater with adjustable temp. and I'm not sure what the water temp should be. I know the beer temp is supposed to be at 70-ish and that inside the fermenter the fermentation process can add 10-15 degrees to the ambient heat. So I assumed that 55-60 is good, but then I was reading about how water conducts heat and how it pulls heat out of whatever is in it and that's why water feels colder than air at the same temp.

So my question is: if my water heat is 60 will the fermentation process still raise the heat inside? Or will the water be so good at conducting that it will even it out to the same temp as the water.

I'm brewing one gallon batches and my fermenter is glass.

Thanks!

You have the right idea. It's about thermal mass and conductivity. When I've measured the temperatures it's been less than a degree different from the fermenting beer to the water.

Here are details:
http://www.woodlandbrew.com/2012/12/fermentation-temperature-control.html

 

[user 141939]

Came here to also say just set your temp to what you want your beer at. They will be very close. I've taken temps of actively fermenting beers in my water bath and they were the same temp.

This is one thing I love about the water bath. It simplifies things.

My current setup is a stc-1000 controlling the heater and a little cheaper aquarium pump to move the water around. It keeps everything within 0.3C.

 

[Brew_G]

I just put together an aquarium heater setup for my most recent batch (brewed two days ago) because I was having trouble keeping temps warm enough, and I think I ended up with a carboy of movie popcorn last time around.

I put my 66F wort-filled 6.5-gallon carboy in a 10-gallon rope-handled bucket and added 57F water to the bucket, then placed the 50W heater in it and set it to 67F. I then (slightly over) pitched a very healthy starter of harvested Bell's yeast. Water temps got up to 69F on my Polder thermometer within about 18 hours and the strip thermometer in the carboy is reading 70F. Temp has remained steady for the last 30+ hours. I occasionally turn on an aquarium pump to circulate the water a bit. Once primary fermentation is over, I'll raise the temp by 4 degrees over a few days to let everything clean up, then I'll set at 65F for the last couple days.

Good luck with yours!