Controlling temp in warm water bath

[Louise Rayment]

Hi, l'm brewing my first batch (5 gallons of IPA). I'm fermenting in my cold garage and I'm controlling temp by immersing my carboy to half way in a warm water bath heated by an aquarium heater on a timer switch. I've got a stick on thermometer on the carboy and temp fluctuates between 66 and 70F. My questions are this: Has any one else used a similar method of temp control and if so has there been any adverse impact on beer due to the bottom half of the carboy being warmer than the top? Also, is the fluctuation between 66 and 70F likely to impart any unplanned results on the beer? Thanks.

 

[deks77]

You'll probably be alright.. 4 degrees isnt that bad of a swing. Ive had some wild swings near the end of fermentation without much impact.. I usually have heat problems, but have put a hair dry in my fridge for heat this winter lol.. If you get hooked a mini fridge off craigslist for 30 bucks and a 15 dollar controller off amazon has been my best purchase..

 

[Calder]

You are good. I'm surprised you have that much of a temp swing.

The beer will be at the same temp as the water bath (within a degree), and the top will be the same temp as the bottom. The thermal mass of the water is way more than the air, therefore the effect of the air temperature is minimal.

All my beers sit in a water bath in my basement. Mostly to prevent run-away ferment temps, but I also use an aquarium heater to raise temps to the 80s for Belgians.

 

[deadwolfbones]

I do the same thing with a sous vide wand, which is a bit more precise. But yeah, you'll be fine with that kind of swing.

 

[Jtk78]

I have used this method in the past with very good results. I filled the water as high compared to the wort line as possible, so I only had about 2 inches of wort above the water line. Keep in mind, during active fermentation, the wort is actually mixing itself up pretty well. The other thing I did was added a small aquarium pump to the water to prevent hot spots in the water. May have been unnecessary, but I already had it

 

[AnOldUR]

Another water bath fermenter here. I use a cheap aquarium pump in the bath to be sure there's no stratification. Just drop it in. No hoses attached.