How to Turn Your Corny Keg into a Fermenter

An often overlooked application for a Cornelius Keg is to use it as a fermenter. There are many advantages to fermenting in a Cornelius Keg and turning your Cornelius Keg into a fermenter is actually pretty simple.

Most home brewers will ferment in either a plastic bucket or a glass carboy. The problem with plastic buckets is they are easy to scratch and scratches lead to little hiding places for bacteria. Cleaning and sanitizing plastic buckets becomes critical and if you’re not careful can easily lead to foul tasting beer.

Glass carboys offer a much better fermenting container but they are hard to handle. Especially when filled with wort they can become heavy and very hard to handle.

Enter the Cornelius Keg. With a little modification you can have a stainless steel fermentation container that is easy to use and handle. One thing that most home brewers don’t realize is that Cornelius Kegs are listed as 5 gallon kegs but will actually hold closer to 6 gallons by volume. This extra space is just what you need to make fermentation in the Cornelius Keg easy and clean.

2 Tricks for Turning Your Cornelius Keg into a Fermenter:

  1. Remove the gas (IN) fitting on the Cornelius keg. You will need a wrench or socket to fit the fitting. Remove fitting. Clean and sanitize the area. From your local beer supply store get a grommet to fit the hole with a 3/8” inside diameter after installation. This will allow you to use an air lock or blow off tube in your Cornelius keg fermenter. A blow off tube is recommended due to the krausen that is produced with today’s yeast strains being used. Sometimes an airlock can get plugged with the krausen and cause a mess. Clean and sanitize as usual and ferment away.
  2. Remove the cap from your corny keg. Drill a 1/2 diameter hole in the center of the cap or take it to a friend and have it done. Remove any burrs from the drilling operation. Clean and sanitize the cap. Get a standard grommet used in bucket lids, sanitize and install in cap. This will allow you to use an air lock or blow off tube in your Cornelius keg fermenter. A blow off tube is recommended due to the krausen that is produced with today’s yeast strains being used. Sometimes an airlock can get plugged with the krausen and cause a mess. Clean and sanitize as usual and ferment away.

With these two simple tricks you can turn an ordinary Cornelius Keg into a stainless steel fermenter and start fermenting like the pros.