Balancing Your Keg System
My first introduction to kegging came back in 1996 when my then roommate picked up a kegging system to avoid the tedium of bottling. What he went through to get his beer carbonated and then to dispense the beer was enough to make me avoid getting a kegging system for many years. After he did manage to get his beer somewhat carbonated, every time he sat down for a beer he had to fiddle around with the CO², regulator, and keg. The fiddling would include: decreasing pressure, bleeding the keg, pouring test glasses, adjusting the pressure again and again, finally getting a half decent glass, then raising the pressure, and putting everything away. The end result was glass after glass of foam or foam and a little beer. By the time you were done drinking you may have poured one or two decent glasses however, even the decent glasses were just that, only decent.
It Doesn't Have to be Hard
Every glass can be a good glass and you don't have to go through all the mucking about to achieve that goal. All it requires is getting your kegging system balanced. What you're balancing is the amount of pressure inside the keg with a roughly equal resistance to pressure on the dispensing side. The result is the beer flows smoothly keeping its carbonation and doesn't act like warm can of soda you've shaken and popped the top on. To balance your system all you need one small formula.
P = L * R + H ÷ 2
P = Pressure in the keg in PSI
L = Line Run in feet
R = Resistance of the line per foot
H = Height from the middle of the keg to the tap/faucet in feet
To some this may seem complicated but it really quite simple and a great deal of precision is not required.
Putting it into Practice
First thing you need to decide is at what temperature your are going to be serving your beer (or any other carbonated beverage). Generally, ales are served at ~55° and lagers slightly cooler at ~48°. A good rule of thumb is the darker the beer the warmer the serving temperature. The stronger ales like Old Ale, Barleywine, and Imperial Stout should be served near room temperature. If you plan on serving both ales and lagers I would serve them at the cooler temperature and allow the ales to warm up on their own. 1
Next you'll have to determine the correct volumes of CO² for your beverage. If you don't know how much CO² you want or the best way to get it into your beer you can take a look at my page on Easy Force Carbonation.
Armed with these two bits of information we can move forward. Lets assume we have a Bohemian Pilsner we want to dispense. We've carbonated with 16.5 PSI of CO² at 48° to create 2.5 volumes of CO² inside the beer. The 16.5 PSI is our "P". Lets plug it into the formula.
16.5 = L * R + H ÷ 2
Now that we know the pressure inside the keg, we need to balance this with resistance. On the right of the equation we have "H". This is the height of your system measured from the midpoint of the keg to the end of the tap or faucet. This is the pressure required to lift the beer against gravity. All systems will be different but we'll use my converted freezer kegerator as an example. The distance between the midpoint of the keg to the faucet on my system is 2 feet. Plugging this into the formula we get:
16.5 = L * R + 2 ÷ 2
Next we have to determine the resistance of the tube we are using to get the beer from the keg to the tap or faucet. The resistance varies based material and internal diameter (ID) and from manufacturer to manufacturer. The manufacturer of your tube will be able to provide you with the exact resistance but a good rule of thumb is that 3/16" ID tube (the most common size) has a resistance of ~2 lbs per foot. This approximation is good enough for our purpose. 2 Plugging this into the formula we get:
16.5 = L * 2 + 2 ÷ 2
All that's left is to rearrange the formula to solve for how much tubing we need.
16.5 = L * 2 + 2 ÷ 2
15.5 = L * 2
L = 15.5 ÷ 2
L = 7.75
So we need 7.75 feet of 3/16" ID beer line to balance the system. 3 The math is really quite simple but if you'd like to quickly play with the number you can use the above Balance Calculator.
Well there you have it, happy drinking with your now balanced kegging system and may you never have to muck about again!
Useful Bits & Troubleshooting
Setting up a balanced system means you won't have to continually increase and bleed off excess pressure. Excessive bleeding off of gas is felt by many, including myself, to reduce or eliminate delicate hop and malt aroma. It is also extremely wasteful of CO² as you are literally venting your money into the air. Repeatedly opening and closing your kegerator, or converted refrigerator or freezer is also wasteful of electricity as you allow warm air in that has to then be chilled.
Contrary to what Anheuser-Busch is trying to tell us with their "2 second pours", beer on a properly balanced CO² system without gimmicky equipment should take about 6 seconds to fill a pint. This of course does not apply to every beer. Hand pumped or nitrogen pushed beers should take longer. Guinness is a perfect example. A proper 2-stage pour of Guinness should take 2 minutes to pour a pint. This of course has more to do with presentation than the setup of the system. However, in a balanced system, presentation aside, you should not be able to fill a pint in less than 6 seconds and if it takes much longer you should shorten your beer line.
When setting up your system always put a check valve between the regulator and keg. This prevents beer from backing up the gas line and fouling the regulator. It's also a good practice to never hook up a keg without first applying pressure to the gas line. Without a pressurized line beer is very likely to back up the line fouling it.
Only use line designed to move liquids for human consumption. In other words always use beer line. These tubes are constructed of FDA approved materials (usually PVC) and have smoother thicker walls. Tubing you buy at the local hardware store is usually unsuitable for anything but gas lines.
Many kegs can be served off of one regulator provided you will serve them all at the same pressure. Manifolds can be created out of T's and check valves. If you want to have two or more beers (or other beverages) served at different pressures then all you need is to add a second regulator. Serving at two different temperatures is also possible but more difficult.
How much beer is in that line? 1/6 oz/ft in 3/16" ID beer line, 1/3 oz/ft in 1/4" ID beer line, 3/4 oz/ft in 5/16" ID beer line.
| Problem | Cause | Solution |
|---|---|---|
| Foaming | ||
| Unbalanced system | Read the above again. | |
| Agitation from movement or force carbonation | Let the keg rest chilled overnight. | |
| Kinks or sharp bends in beer line | Tubes should run straight or in gentle spirals. | |
| Tap / Faucet opened partially or slowly | Taps and faucets should be opened quickly and fully. Partially closed taps and faucets cause extra restriction and turbulence causing CO² to come out of solution. | |
| Dirty beer lines | Clean regularly with beer line cleaner per manufacturer's directions. | |
| Warm line, tap, or faucet | Heat causes carbonation to break out of solution. Keeping beer lines, taps and faucet cool keeps the beer cold and the carbonation in solution where it belongs. | |
| Old beer | Drink faster. | |
| Sanitation | Clean taps, faucets, beer line, kegs, CO² lines, fittings. Anything that comes into contact with the beer or CO² is a source of contamination and should be cleaned and sanitized regularly. | |
| Flat Beer | ||
| No or improper carbonation | If force carbonating follow the guidelines on the force carbonation page. | |
| Leaks | Double check that connections are properly seated and tight. Diluted dishwashing detergent can be used around connections to find leaks, just follow the bubbles. Keg pressure testers can be useful in spotting slow leaks. | |
| No Head or Head Fails Rapidly | ||
| Beer style / Brewing Technique | Some styles aren't well know for having voluminous heads. Some have low levels of carbonation and others have ingredients that prevent large head formation. Cleaving of proteins. | |
| Grease / Fat | Grease and/or fat on your glasses or in containers that touch your beer will prevent head from forming. Clean well, rinse with clean water, air dry. Keep hands out of glasses and remove lipstick promptly. | |
| Detergent / Soap | Detergents and soap residue will reduce or prevent head formation. Rinse thoroughly with clean water. | |
| Wet glass | Allow glasses to air dry before pouring. | |
| Tap / Faucet opened partially or slowly | Taps and faucets should be opened quickly and fully. Partially closed taps and faucets cause extra restriction and turbulence causing CO² to come out of solution. | |
| Beer too cold | When the beer is too cold not enough CO² may come out of solution to form a good head. Either increase the temperature of the beer or pour at a greater height. | |
| Faulty regulator | Carbonation may have taken place at a lower than expected pressure or the keg may be being served a a lower than expected pressure. A keg pressure tester can confirm correct pressure. | |
| Leaks | Double check that connections are properly seated and tight. Diluted dishwashing detergent can be used around connections to find leaks, just follow the bubbles. Keg pressure testers can be useful in spotting slow leaks. | |
| Off Flavors | ||
| Sanitation | Clean taps, faucets, beer line, kegs, CO² lines, fittings. Anything that comes into contact with the beer or CO² is a source of contamination and should be cleaned and sanitized regularly. | |
Notes
1 Most Americans drink beer that is too cold when compared to traditional practices. This is a result of the American love affair with lagers and a response to the climate of much of the US being drastically warmer than the European regions where the styles were created. As beer temperature decreases more carbonation is kept in solution decreasing aroma and increasing carbonic acid bite, the perception of malt flavor decreases, and the perception of bitterness increases. This can dramatically affect the perception of a beer. However, personal taste is what this hobby is all about. Use your taste as your guide. Serve your beer at the temperature it tastes best to you.
2 Actual restriction of 3/16" ID beverage tubing range between 1.7 and 3 lbs/ft. Using a low average of 2 lbs/ft allows for more restriction rather than less and helps to account for variables not in the equation like restriction from the tap/faucet.
3 Sometimes you may need a longer tube run than the formula suggests. For example you have your beer in the basement fridge and you want to run a line up to your bar. The distance from the middle of the keg to the faucet may be 10 feet. Solving the equation we get a run (tube length) of only 5.75 feet. Obviously not long enough. Not a problem. Just switch to a larger less restrictive tube. For 1/4" ID beer lines use the manufacturers listed restriction or an estimated "R" of 0.6 lbs/ft. For 5/16" ID beer lines use the actual or 0.2 lbs/ft. Generally, for lines under 9' use 3/16" ID, under 25' use 1/4" ID.
