Keeping your Fermentor Cool with a Ghetto Bucket


Evaporative Cooling to Keep Beer Cool (The Ghetto Bucket)

[Ghetto Bucket setup in a romantic bath tub.] 

One of the biggest key ways to go from good beer to great beer is by controlling your fermentation temperature.   Because higher and uncontrolled temperatures during the first few critical days of fermentation can cause off-flavors in your beer such as excessive esters and fusel alcohols, it’s important to keep your ferment temperatures cool and consistent.  There are a few ways to do this, but for those summertime brewers who lack a consistently cool basement, or a spare refrigerator with a temperature controller, here’s a low-tech way of keeping your beer cooler during fermentation.

The Ghetto Bucket Method:

Basically you’ll be creating a water bath for your fermentor (Ale Pail/carboy) to keep cool and you’ll only need a few things to make it happen:

Stuff You Will Need:

1. A plastic bucket or ice chest that you can stick your fermentor bucket or glass carboy in.

2. A fan.

3. A bath towel or large t-shirt.

4. Some ice or frozen water bottles.

5. Some way to measure the temperature of the water surrounding the Ale Pale/carboy or the fermenting beer itself (stick-on-strip thermometer, water-safe thermometer or thermowell setup).

If you want to get super ghetto, you can forego the fan and wet bath towel and just add ice around the bucket as temps start to rise.


If you get a little less ghetto, here’s what you do:

1. Wrap your Ale Pail or carboy up with a bath towel; this can be somewhat easier when the towel is wet.  Alternatively, you could use an old large, dry t-shirt and stretch it around your fermentor.

2. Place your bundled up fermentor bucket into a larger plastic bucket.

3. Pour cold water around your fermentor bucket so that it fills the plastic bucket it’s sitting in up to about beer level.

4. Add ice or frozen water bottles to the plastic bucket periodically as your temperature rises to cool the temperature of the water.

5. Direct a blowing fan onto the wet towel.  

The basic idea is to use the process of evaporative cooling to keep your brew at cooler fermentation temperatures in order to control potential off-flavors caused by higher temperatures.  The bath towel (or t-shirt) will act like a wick, pulling chilled water from the plastic bucket up and around your fermentor, while the fan cools the wet towel further.  You can check the temperature of the water with a temperature probe or by placing a stick-on-strip thermometer on the side of the plastic bucket.  This will give you a close idea of what the temperature inside your fermentation bucket/carboy is.  If you want to get a more accurate temperature read, buy a thermowell and attach it to your carboy. [A thermowell is essentially a probe used to measure temperature that fits through the mouth of a carboy and extends into the center where fermentation is most active.]

Just remember that fermentation temperature is usually warmer in the center core of the carboy (or Ale Pail) by about 1 – 2 degrees, so keep this in mind if you’re just using a stick-on-strip thermometer.   This may mean that you’ll want to keep the water temperature at or just below your planned fermentation temperature, which for most ales is between 62-68°F (16.67-20°C). Keep in mind that temperatures during active fermentation can be in excess of 10°F (5.56°C) higher than the surrounding air, which is especially true with high gravity beers such as barley wines or quads.  Placing your fermentor bucket in cool/cold water can reduce this differential, but even so, during the most active part of your fermentation (usually the first 1-4 days when your bubbler is popping every second or two), the temperature inside your fermentor will still be a few degrees warmer. 

Ok, so now you know how to keep your fermenting beer cool, ghetto style.  If you’ve got no other options, this is a great way to go.  That said, here’s what’s going to annoy you about this setup:

1. As neat as it is to hear the sound of your little baby fermenting batch of homebrew bubbling away for the first hour or so, this bubbling will continue on incessantly for at least the first 4-6 days of fermentation.  And although you might not be able to hear it in the photo above, that huge floor fan made it sound like I was testing out a jet engine in my bathroom.   In other words, if you’re sleeping somewhere close to your homebrew, invest in some ear plugs.  

2. Hope you don’t have any plans while your beer is fermenting because you’re going to be checking in on your water temps every so often and running to the freezer for ice at least every 10 hours (depending on your house temperature) to make sure your beer isn’t getting too warm.    

3. Were you thinking about trying your hand at a lager? Let me know how keeping your beer at constant near freezing temperature for weeks with the ghetto bucket works out for you.

4. Remember to multiply the annoyance factor of the ghetto bucket by however many batches of beer you plan on fermenting.

Ready for the real burn?  For about the same price of the ghetto bucket setup, you could have gotten yourself a free or inexpensive refrigerator from craigslist and purchased a temp control online (or from your local homebrew shop) and avoided headaches 1 – 4 from above.  BURN NOTICE!!!

This is why I used the ghetto bucket exactly once before I took the floor fan back from whence I purchased it, and got myself a free refrigerator and a set-it-and-forget-it temp control and haven’t looked back since.

Now if there were only some place where some helpful soul could take some of the leg work out of making the right decision when it comes to choosing a refrigerator/temp control combo…  Where to look…

[Psst- No promises, but there‘s a link just below this sentence entitled “Convert a Refrigerator Into a Fermenting Chamber”, and it might be just what you’re looking for; but don’t take my word for it… I’m just a questionably punctuated, borderline run-on sentence.]  

Related link: Convert a Refrigerator Into a Fermentation Chamber



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