Since I was going to be making ten gallon batches at a time, I decided that I needed a large primary fermenter. Here are the ones that I thought about:

Fermenter Type: Advantages: Disadvantages:
Glass Clear Heavy
Difficult to Clean
Plastic Light
Prone to Scratching
Stainless Steel Extremely Durable
Easy to Clean

I decided to go with a converted SS keg for a primary fermenter. The reason that I include inexpensive in the table above is that I found an old Coors keg at a garage sale for $5. Since this keg has rounded sides, it was not suitable for the my three tier system, but it seemed very suitable for a fermenter.

Many people have converted kegs into primary fermenters. In searching the HBD Archives I found that many people have gone to quite elaborate means to convert their kegs to a "closed" fermenter. I decided to take a simpler route and use my keg as an "open" fermenter by cutting out an opening in the top that was the same diameter as a standard stock pot lid. After filling the fermenter with wort and pitching the yeast, I put the stock pot lid on and put the fermenter in my chest freezer which is set to fermentation temperature. After one to three weeks of primary fermentation depending on whether I am brewing an ale or a lager, I rack to glass carboys for secondary fermentation.

The stock pot lid and the positive pressure of CO2 from active fermentation are adequate for keeping any beasties out during the primary fermentation. An advantage of open fermentation is yeast harvesting, which I plan on trying in the future.

After the wort is cooled and the yeast is pitched, I aerate continuously for several hours with an aquarium air pump to provide the yeast with oxygen for their growth phase. I sterilize the silicone tubing and the stainless steel pipe by boiling and an iodophor soak. I don't use an airstone, because it caused the foam to overflow the fermenter.

Here are two images of the same beer during primary fermentation. The picture on the left was taken fourty-eight hours after fifty degree Fahrenheit wort was placed on top of the yeast cake of a previous lager. Here, the beer is at high krauesen.

This picture was taken two days afterward. The head has fallen, but the beer is still fermenting very actively. This beer will remain in the primary fermenter for two weeks, and then be placed in glass carboys for lagering.

Carboys waiting to be filled with beer.

Here is a close up picture of my lagering freezer. Beer is stored here for several months at a crisp thirty-three degrees Fahrenheit, awaiting it's next destination, a keg. I can store up to eight carboys here, and if there is any room in my serving freezer, a couple more there as well.