Every homebrewer dreams of the day when they can kiss bottling goodbye. Upgrading to a kegging system says a lot about you. You like control. Quality. You’re committed. So when you pour your hard earned cash into a draught system, foam is no longer acceptable. Besides, you spent hours on that beer. Cleaning, sanitizing, designing the perfect recipe. You navigated fire, boiling liquid, heavy equipment and you clearly have patience. All that hard work for a nice cold glass of foam? I think not.
So why do we experience foam at home when our favorite neighborhood watering hole seems to have figured it out? The answer is balance. Draught dispense relies on 3 key variables and they all need to work together. If one or more variables isn’t right you’ll find yourself sipping a sudsy snifter. The concept behind this can be quite complicated. There’s math involved. Science. Physics. Boring. This is homebrewing, dangit! It’s supposed to be fun! Here’s the quick and easy guide to finding that perfect balance.
- Temperature – Beer can be served at different temperatures depending on style, equipment and tradition, but temperatures over 40°F are problematic. The warmer the beer the more foam you’ll have. The most stable temperature for draught beer is 38°F. Take the temperature of your beer in the glass, though, not the fridge, because beer can warm up in the line as it travels to your glass.
- Applied Pressure – Applying CO2 pressure to the keg keeps your beer carbonated and allows you to push beer from the keg to the faucet. Too much pressure and your beer flows too fast causing CO2 to break out of solution. Too little pressure and your beer goes flat in the keg. A simple internet search for “Carbonation Chart” will help you determine the correct applied pressure. For most styles, at 38 degrees, aim for 8-10psi.
- Restriction – The length and inner diameter of your beer line matters. Beer needs to slow down before it gets to your faucet. The smaller the diameter, the more restriction you get. 3/16” inner diameter tubing is perfect. Start with 5ft. If temperature and pressure are right, a pint should take 7-8 seconds to pour with no excessive foam. If it takes longer, try shortening your line by 6 inches at a time.
Kegging systems take on different shapes and sizes but the fundamentals stay the same. Balance these 3 variables and I promise you’ll be on your way to a perfect pint. Cheers!