The dreaded foamy pour is a common complaint among new kegerator owners and operators. While professionals enjoy the benefits of commercial-grade refrigeration and purpose-built draft systems, we home enthusiasts often cobble together our own setups from Craigslisted parts and fire-sale fridges. And diagnosing foam is almost always part of the process. If your draft system consistently serves supremely sudsy pints, you may need to get to know the muffin fan.
First things first. Before you start hacking your kegerator, make sure your draft system is balanced. A balanced draft system includes enough flow resistance in the beer lines and from gravity to just offset the carbonation pressure of the beer. For whatever reason, 5-foot beverage lines are standard issue for most kegerator conversion kits, but many find that longer lines (up to twice as long) are required for foam-free flow. So check your lines first. When in doubt, go long and trim back as needed.
Once you’ve convinced yourself that balance isn’t the issue, then it’s time to think about temperature. Warm air rises and cold air sinks, and most refrigerators don’t supply much in the way of internal airflow. So, it’s entirely possible, especially if you operate a draft tower, that beer exiting the faucets is 5-10°F (2.5-5.5°C) warmer than beer leaving the keg. And because warm beer holds less carbon dioxide than cold beer, it releases that excess carbon dioxide when you pour it. If the first pint is foam but subsequent pints are fine, then temperature is probably your problem (that first pour cools down the lines).
Enter the muffin fan (please don’t ask me why it’s called that because I’ve no idea). A muffin fan is nothing more than the simple fan that cools components inside your computer, and it offers a simple and inexpensive way to keep air moving inside your kegerator. Home drafters typically use them in one of two ways:
1. Installing a muffin fan anywhere inside a refrigerator helps reduce stratification (vertical temperature gradient) by preventing cold air from settling at the bottom. The size and shape of your fridge will determine where you can fit a fan. A fan near the bottom can push air upward, while a fan mounted near the top may need an intake tube to draw cold air up from the bottom. Ultimately, keeping the air moving is the goal.
2. A muffin fan can also be used to push cold air up and into the draft tower itself, keeping beer lines cool all the way to the faucets. In this scenario, the fan is placed at the bottom of the fridge (where cold air settles), and the fan’s output is directed through a flexible tube that extends up into the draft tower. Those who live in warm, humid climates should, however, be prepared for a great deal of condensation to form on the outside of the tower!
Draft tower cooling kits can be purchased ready-to-go from many homebrew stores, no wiring required. Online vendors also offer ready-made kits, a few of which include:
- Apex Brew Wares
- The CHI Company
- Kegman
- Ebay
Professional-grade cooling equipment is also available for those who demand the ultimate in home-draft quality. These are the same high-quality, high-flow systems that come preinstalled in commercial kegerators used by professionals:
- Beverage Factory
- Micromatic
You can also build your own cooling system to meet your specific needs. Muffin fans are available at any electronics store, or you might even have one sitting in an old computer, just waiting to be repurposed. All you need is some kind of enclosure and a length of flexible tubing to direct flow up into the draft tower. The details of such a build are beyond the scope of this article, but HomebrewTalk.com user Buford offers an excellent primer as part of a larger guide to building a kegerator from the highly-coveted Sanyo 4912 mini-fridge.
If you do choose to do it yourself, please remember that you’re installing an electrical device inside the potentially wet interior of a refrigerator. Put safety first and take all of the necessary precautions, including use of a ground fault circuit interrupter (GFCI) electrical outlet.
Once installed, your muffin fan should help keep more consistent temperatures throughout your kegerator. And that translates into less foam and more beer for you.