Controlling temp in a poorly insulated house

I've read through many of the temperature control threads here and elsewhere. Most of them are focused on how to lower the fermentation temperature of ales in the summer. I live in the SF Bay Area in a poorly insulated house, and as we move into Fall the temps are dropping into the 40sF at night outside and into the low-50sF inside.

The only space I have for the fermentation equipment is in a completely uninsulated basement. At this time of year temps could get as high as 80F during the day in there and as low as 45F at night. That is a large range.

How do I regulate temps in an environment that might be both too hot and too cold? I'd like to hear your thoughts on the best way to do that, keeping the following in mind:

1. My funds are limited
2. I'm not the handiest guy, i.e. I lack the skills to build a super-deluxe fermentation chamber.

For heating I've seen the FermWrap heater recommended on another site. This kit on Northern Brewer looks like it might work. Problem is this doesn't help if it gets too hot in the basement in the middle of the day. It's also a bit more than I want to spend.

Thanks for any ideas you have.

For evening out your temps, I recommend lots of water. The more the better. Get a large Rubbermaid container and put your carboy/bucket in that. Fill it up with water until just below the level of the wort inside. This will lessen the wild temperature swings. For chilling, you can put ice in the water. For heating, you could possibly use an aquarium heater in the water, depending on how much heat you need.

a) your BASEMENT doesn't swing 40 degrees, so don't panic. Also, look into getting a brew belt if you want nice healthy ale temperatures (though I do not recommend using on glass carboys----waiver).

b) yes, I second the tupperware tub with water (you can 'wick' a t-shirt--cotton--over your ferm. container into the water also). That's my lagering unit until I get my freezer setup.

Good luck! And hey you can do some good California Commons/Steams!

A cooler+aquarium heater is usually able to maintain close to a 70F temp, with your carboy/fermenter plopped in. Mine was about $20 and can be dialed down to about 68F in my setup.

you could use this guy for inspiration.




Sorry, I just wanted to be able to use this image


On a serious not, get a large tote, fill with 1/2 - 3/4 water, place a aquarium heater in that goes down to 65. They are keep the water within 1 degree all day long. It is hard to believe that a basement would get to 80 during the winter in San Francisco.

It's amazing how much the temperature swings are between San Diego and San Francisco. San Diego doesn't have too much of that problem, however it does have a tendency to get to about 40F in the winder at night, which is why I put together a fermentation chamber in the garage. I'm really not sure how well those temps can be evened out without one. All you'd really need is a cooling unit with the insulated chamber, as the insulation would help to keep it a certain temperature at night when the outside temp drops, and in the day it would kick on when needed.

But on low funds, do what those above said. Otherwise, you could probably find a small fridge on craigslist for about $30 and the insulation (for 2" thick) is $24 for a 4x8 foot sheet. You could possibly do it for $50 or less, holding it together with duct tape, if you found a good enough deal on the fridge.

nebben said:

A cooler+aquarium heater is usually able to maintain close to a 70F temp, with your carboy/fermenter plopped in. Mine was about $20 and can be dialed down to about 68F in my setup.

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Yep, that's what I do. A water bath, with a floating thermometer. It minimizes fluctuations since the water insulates so well. It takes a LONG time for the beer and the water to change temperature! I use frozen water bottles to make lagers and an aquarium heater for ales. It works great! I can maintain temps in my basement for fermenters from 34 degrees up to 72 degrees that way!

YooperBrew said:

Yep, that's what I do. A water bath, with a floating thermometer. It minimizes fluctuations since the water insulates so well. It takes a LONG time for the beer and the water to change temperature! I use frozen water bottles to make lagers and an aquarium heater for ales. It works great! I can maintain temps in my basement for fermenters from 34 degrees up to 72 degrees that way!

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Okay, this seems do-able. So I get a large Rubbermaid container and fill it with water, then put the carboy in. During the day, if the temp gets too high (which it probably won't at this time of year, but...) I put in frozen water bottles to bring the temp down. At night, before I go to sleep, I turn on the aquarium heater and set it to 68 or something?

And it's possible to do lagers this way? Cool! How many times a day do you need to put new frozen water bottles in when you're doing a lager?

This thread popped up at the perfect time. I just started looking into how to heat my fermenter! Big tote and an aquarium heater sounds like the perfect solution for my situation.

switters said:

Okay, this seems do-able. So I get a large Rubbermaid container and fill it with water, then put the carboy in. During the day, if the temp gets too high (which it probably won't at this time of year, but...) I put in frozen water bottles to bring the temp down. At night, before I go to sleep, I turn on the aquarium heater and set it to 68 or something?

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The key is to find a aquarium heater that goes as low as possible. I found it hard to find ones where the dial went below 68. I found one that went down to 65 but is at home and can't remember what it is right now.

Good thread guys... I will be using some of these answers my next brew. I live in an old house and we do not have the furnace turned on yet for the winter. Temp swings are pretty severe in here. Has anyone considered ( I THINK I asked this before) a submersible ( completely cleaned and sterilized of course) aquarium heater? They are not overly expensive and can be dialed in to maintain a temp pretty easily....Just set it...drop it into the wort and snap the lid on.

Here is an aquarium heater that goes down to 65F. Not too expensive.

EDIT: Found it for $15 instead of $22 and replaced the link.

switters said:

Here is an aquarium heater that goes down to 65F. Not too expensive.

EDIT: Found it for $15 instead of $22 and replaced the link.

Click to expand...

that one says it is not totally submersible.....I think you would want one you could just drop in the fermenter.... I used to have a LOT of aquariums ( at one time I had a 125...two 55's....a couple of twenty's and a 35 hex all going) I can't recall the name but in the 125 I had two heaters I could bury under the rocks and they kept 125 gallons of CIRCULATING water right at a steady temp no matter what the ambient was doing.

Yeah, the tubs/totes are the way to go. And the key is that liquid (ie: water) takes longer to switch temperatures than air, so you will not have swings (ie: think about winter when lakes freeze but only so deep, right?).

Ok, I did some searching on here and it seems a heater IN the wort is a no no due to sterilization AND the heaters get REALLY hot, and contacting the yeast can kill it. Seems a tote with water and the fermenter in THAT and a heater in the tote water is the way to go.

OHIOSTEVE said:

Ok, I did some searching on here and it seems a heater IN the wort is a no no due to sterilization AND the heaters get REALLY hot, and contacting the yeast can kill it. Seems a tote with water and the fermenter in THAT and a heater in the tote water is the way to go.

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Yeah, that's where I thought I'd be putting the heater (in the tote water, not in the fermenter). If this is true, it doesn't matter whether the heater is fully submersible or not, does it?

switters said:

Yeah, that's where I thought I'd be putting the heater (in the tote water, not in the fermenter). If this is true, it doesn't matter whether the heater is fully submersible or not, does it?

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nope.. They will have suction cups you can stick it to the side of the tote.. I'd probably tape the cord also in case the suction cups let go.

I bought the Submersible type . Its nice to just drop it in and not worry about it . I got it at Petco and are on sale now for $ 19.99 internet special. heater

springer said:

I bought the Submersible type . Its nice to just drop it in and not worry about it . I got it at Petco and are on sale now for $ 19.99 internet special. heater

Click to expand...

Does that one go down to 65F?

One thing I did when I was first trying to control my fermentation temps was to give myself easy, accurate access to fermentation temperatures. I've never cared for the LCD sticker thermometers you stick directly on the fermenters. What I did was drilled a small hole in one of my fermenter lids, and stuck a dial thermometer in there, so I could constantly monitor my temps and adjust my swamp cooler as needed.

I'm in Berkeley in an old uninsulated 1920's house and I just use a swamp chiller to keep temps constant. It's been relatively cold this week, but still good enough.

springer said:

I bought the Submersible type . Its nice to just drop it in and not worry about it . I got it at Petco and are on sale now for $ 19.99 internet special. heater

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What is the advantage of the fully submersible model?

theacolyte said:

I'm in Berkeley in an old uninsulated 1920's house and I just use a swamp chiller to keep temps constant. It's been relatively cold this week, but still good enough.

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Meaning you don't need ice bottles or a heater?

switters said:

Does that one go down to 65F?

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I don't recall but I used it for a Saison so I didn't even look that close to the lower temps.I'll take a look tonight

switters said:

What is the advantage of the fully submersible model?

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No worry about it sinking into the water. Just a little piece of mind

I made my fermentation chamber for $106. Check out the link in my sig.

switters said:

Meaning you don't need ice bottles or a heater?

Click to expand...

I did use bottles of ice when we had that mini-heatwave, but right now it's just sitting in my bucket with water up to the wort and a tshirt over the top.

If you can find a cheap used cooler, I'd prefer that over the rubbermaid bin. It would hold the temp a lot more stable.

Bobby_M said:

If you can find a cheap used cooler, I'd prefer that over the rubbermaid bin. It would hold the temp a lot more stable.

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How large does the cooler need to be to fit a 6.5 gallon carboy?

switters said:

What is the advantage of the fully submersible model?

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As said above, its more about convenience. Keep in mind though that the heating element in an aquarium heater should always be submerged or its a fire risk

switters said:

How large does the cooler need to be to fit a 6.5 gallon carboy?

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I use an Igloo cooler (the Ice Cube model). I took off the lid (which is hollow anyway) and made a lid out of three or four layers of foam. It works great!

YooperBrew said:

I use an Igloo cooler (the Ice Cube model). I took off the lid (which is hollow anyway) and made a lid out of three or four layers of foam. It works great!

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That's a great idea. I just remembered I have an Igloo Ice Cube cooler in the basement. My 6.5 gallon carboy does fit in it, but the top 1/5 of the carboy is exposed. I think your cooler is larger than mine. Still, I may be able to fit some kind of top over it to prevent heat loss.

switters said:

That's a great idea. I just remembered I have an Igloo Ice Cube cooler in the basement. My 6.5 gallon carboy does fit in it, but the top 1/5 of the carboy is exposed. I think your cooler is larger than mine. Still, I may be able to fit some kind of top over it to prevent heat loss.

Click to expand...

Stack enough styrofoam to make up for the height deficiency and cut the centers out of the stack. ( basically make a styrofoam donut) that sets down on the lip of the cooler. take a piece of styrofoam and make it a lid with a small hole for the airlock to stick through.

I would probably get a larger heater than I thought I needed also. You are heating the water to heat the wort so I think a bigger one may be more efficient.

It's not a question of the swing in air temperatures. Air is way less dense than a liquid like water or beer, and the swing in 24 hours will be much, much larger in the air than in the liquid.
The first instructive thing to do is take temperature readings of the beer over a 24 hour period and find out what the swing of the liquid is. I'll wager you'll find that it's a small fraction of the air temperature swing. The difference of the amount of heat retained as a function of the density of the medium is sometimes called the "thermal flywheel."
This is where a water bath comes in. Some large container in which to immerse the fermenter that has maybe 15-20 gallons of water serves to multiply that "thermal flywheel" and retard even further the temperature swing in the beer. Add the aquarium heater, as some suggest, and you have an inexpensive way of keeping the temperature constant.

Me? I'm lucky to have a basement that runs low '60s most of the year.

Boerderij_Kabouter said:

I made my fermentation chamber for $106. Check out the link in my sig.

Click to expand...

For that price you could get a full refrigerator on craigslist.

OHIOSTEVE said:

Stack enough styrofoam to make up for the height deficiency and cut the centers out of the stack. ( basically make a styrofoam donut) that sets down on the lip of the cooler. take a piece of styrofoam and make it a lid with a small hole for the airlock to stick through.

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Where do you get pieces of styrofoam like this?

switters said:

Where do you get pieces of styrofoam like this?

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They are housing insulation. 1" thick is $13/4X8 sheet and 2" is $24@ at Home Depot in SFBay area

dantodd said:

They are housing insulation. 1" thick is $13/4X8 sheet and 2" is $24@ at Home Depot in SFBay area

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Thanks. I imagine 1" is sufficient and probably easier to work with.

dantodd said:

For that price you could get a full refrigerator on craigslist.

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Did you look at his fermentation chamber build?
It looks like a refrigerator to me . He modified it with a love dual controller so that he can heat the unit or cool it

dantodd said:

For that price you could get a full refrigerator on craigslist.

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Power is not free. Think about that before buying a 2nd refridgerator.