Author Topic: Tips on keeping wort cool?  (Read 3827 times)

Offline btrammel

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Tips on keeping wort cool?
« on: March 30, 2013, 04:58:20 PM »
Hi all.  I just finished brewing Midwest's Liberty Cream Ale (my second batch).  The brew's been in the primary for 2 days now, hovering at temps between 68-72 degrees (still no bubbles in the airlock, even though the lid has been replaced - although I can see krausen).  I'd like to keep the temperature under 70 degrees if at all possible.  I have the bucket sitting in the bathtub in my spare bathroom.  The bathtub is filled to about 4 inches with water.  I will replace the water every couple of days.  I also take a large ziploc bag filled with ice and will place it right up against the bucket every 2 days.

I used this method with my first batch, Midwest's Smooth Nut Brown Ale.  It seemed to have worked pretty well - I think the warmest the bucket got was probably 72 degrees.  However, spring/summer is upon us and it gets pretty hot out here in California.

Do any of you have any tips on keeping your fermenter cool?  Please share - I'd love to hear them!

Thank you,

Offline greatplainsbrewer

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Re: Tips on keeping wort cool?
« Reply #1 on: March 30, 2013, 05:28:36 PM »
I think you're on the right track.  I've used a plastic tub partially filled with water and frozen gel packs.  You can also put a t shirt over the carbon and blow a fan over it.  The shirt will wick the water up and cool the fermenter.  Could also set up a temp controlled chamber. . .

Offline kramerog

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Re: Tips on keeping wort cool?
« Reply #2 on: March 30, 2013, 08:03:18 PM »
I use large plastic totes rather than a tub and use ice packs.  I'm not sure why you put the ice in a ziplock rather than directly in the water.  You are probably changing the water to avoid it getting funky.  I  put in a little bleach instead because of it is easier to keep the bath water stable without changing the water.   

Offline dzlater

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Re: Tips on keeping wort cool?
« Reply #3 on: March 31, 2013, 11:18:25 AM »
 I use the carboy in a tub method as well.
I fill the tub with water up to the level of the beer in the fermentor. And use frozen water bottles to "try" and keep the temps. where I want them.
I think having the water level the same as the beer keeps the fermnetor temps. more stable.
Dan S. from NJ

Offline anje

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Re: Tips on keeping wort cool?
« Reply #4 on: April 01, 2013, 04:27:31 PM »
Another vote for the plastic tub method. The advantage over a bathtub is that you can fill it fuller -- I'd recommend keeping it just an inch or two below your beer level, so you can maximize heat transfer from the beer to the water in the tub and minimize temperature fluctuations. (Also, those liquid crystal stick-on thermometers don't really like being submerged. If you mount it high and horizontal, you can avoid that.)  I found that even without adding ice, the temperature stayed 2-3F below room temperature just due to evaporation.  Since RT in my house is about 67-68F, that drops it to about where I want to ferment an ale.

All that said, I love my new fermentation chamber. I think I will love it even more now that I have a dehumidifier for it so it doesn't turn into a mold factory.
<-- microbiologist brewster n00b.

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Offline ynotbrusum

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Re: Tips on keeping wort cool?
« Reply #5 on: April 01, 2013, 06:41:03 PM »
All good suggestions.  Remember, though that keeping the temperature on the low side for the first 48-72 hours is the most critical time.  After that a lot of guys allow it to free rise with the water in the tub to an ambient temperature with little problem.  After sanitation, temperature control and pitch rates are the 2 biggies to better beers, then water...that's where I'm at still (the chemists start to win out at that point and I'm no chemist!)

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Offline reverseapachemaster

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Re: Tips on keeping wort cool?
« Reply #6 on: April 02, 2013, 02:12:46 PM »
If you're able to keep it steady around 68-72 you're doing pretty well with it and trying to keep it a perfectly even temperature might be very difficult, especially while you are at work or asleep. As ynotbrusum pointed out, you really only need temperature control during the first 48-72 hours, assuming you pitched an adequate amount of yeast so fermentation is starting shortly after you pitched. If you underpitch and the yeast are building their numbers for the first 48 hours you need to account for that additional time.

I couldn't ever get really great results with the bucket of water and ice packs method. It gets way too hot in Texas, even with the AC running because we're just not going to set the AC down in the 60s because it would be way, way too expensive. It's also too humid to do the swamp cooler thing with the t-shirt and a fan. It would just get muggy around the fermentor and it seemed to make it warmer instead of cooler. You probably don't have as serious of humidity but depending on the part of California you might have much hotter days ahead of you. With most ale yeast I wouldn't want it to get over 70-72 so unless you can keep it cooler during the hotter months you'll either have to brew with strains that do better with warmer temperatures or take a break from brewing until it cools off.

One way you can help cool off the fermentor is to drape a towel or shirt over the fermentor so it sits in the water. As the water soaks up into the cloth the air current in the room with blow through it and create cool air. You may need to set your AC to blow on it or use a fan to blow air in that direction. It won't work if you have a lot of humidity but you might have better luck than I did.

You can also enclose the fermentor and the bathtub or a smaller tub of water in insulation with an AC vent. If you have vents on the floor you can put the fermentor next to the vent and box both in together. If you have AC vents in the ceiling you you would have to get creative about how to direct that cold air down to the fermentor. Not sure if that would get it too cool but it certainly would keep it cooler than ambient temperatures.

Ultimately you will probably ditch the water method if you're having a hard time keeping it cool but for your first few batches it doesn't hurt to go with the economical system and work on improving other parts of your brewing technique.
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