Stop the Foam: Get the Perfect Head on Your Beers, Every Time
Going to pour a beer and getting a glass of foam is always a nightmare. You fill up a pitcher just to get 1 pint of beer and a 10 minute wait. There are a lot of reasons that your system may be spewing foam. We will review some of the most common causes to make sure you get the perfect head on your beers. The four main issues relate to temperature, pressure, your beer line, and blockages.
Temperature:
As a general rule of thumb, you want your beer to be ice cold. While some darker beers may be served slightly warmer (especially nitro beers), almost all the lighter brews want to be as cold. CO2 infuses better at colder temperatures, and if your kegerator is sitting too high, the CO2 will not stay in solution nearly as well.
It is important to note the temperature of where the beer is pouring from. If your tower does not have any cooling inside of it (like a built-in fan / tube from your kegerator), there may be a significant temperature difference at the faucet than what is in the keg. This will result in a small burst of foam when you start pouring with a much smoother pour afterwards. Many newer models of kegerators have these tubes from the blower meant to angle up into the tower for just such a purpose, but if you have an older model, you can always buy an aftermarket tower fan like one of these.
When setting the temperature on your kegerator, it is important to think about the range in which it cools. For instance, while I mentioned getting the beer as close to freezing as possible without freezing, you may be thinking of setting it to 33°F. However, this generally means that your system will turn on when it gets above 35°F and click back off when it gets below 31°F. This lower range can cause freezing in both your lines and your keg (see the blockages section below). It is also good to look at how your system cools when you set your temperature. Again, the newer models have a fan to spread out the chill a little more efficiently, but many standard models just use a cold back plate. This means that anything closer to that back wall is going to be remarkably colder than things near the front, even if you leave the door closed for long periods of time. For this reason, if your kegerator cools this way, it is important to keep your beer lines off the back panel.
I recommend setting your kegerator at 35°F and having a thermometer like one of these (each shows what the highest and lowest temperatures within the last hour). I keep my beverage line coiled around my keg so that it doesn’t end up accidentally getting pressed against the back, and I use a tower fan to make sure my tower is as close to the same temperature as my keg as possible.
Pressure:
When looking online, you may find many different charts about what exactly you want your pressure to be based on different styles and their respective CO2 volumes. Most of these are more meant for when you are home brewing and infusing the carbonation yourself, not about the pressure that you want to push pre-carbonated beer. These charts often cause people to be pushing out at 2 to 3 times the recommended serving pressure for their system. Now, while you can change the pressure slightly between your pilsners and your barley wines, they should always remain within a few psi. Unless I’m getting something particularly specialized like a barrel aged stout, I try to not change my pressure at all between different styles. I recommend a nice mid range of 11 psi for most beers.
An important thing to remember is that the gas is a one-way flow and it holds at the highest pressure until that pressure is blown off. This is to say that if you accidentally set your pressure too high (i.e. 20 psi) and then go to move it back down to the affirmation to 11 psi, the regulator will not decrease as you turn it down. The pressure inside the regulator was at 20 psi and it has set the keg at such. Decreasing the pressure is not just spinning the knob on the front of the regulator, removing that pressure. Most regulators will have a PRV (Pressure Release Tab) on the side to do just this. Pull out for a second and release and it will show what the current pressure is set at. If you do not have this blow off tab, you can always engage the sanke keg coupler when it is not connected to the keg and let the gas out that way.
Similarly, when you turn down the 20 psi from the regulator, this does not mean that keg has decreased from 20 psi. There is a one-way gas valve in the keg coupler as well stopping gas from flowing back out of it. Once again you will need to pull the pull tab on the side of the coupler to release the gas from inside of the keg. If the CO2 sat at a high pressure for a longer amount of time, some of the CO2 may have infused into the beverage and will need to be released. This is essentially shaking the keg to release the gases and pulling the PRV repeatedly to blow off any extra internal gases. This process will lose you a bit of flavor out of your beer, but can help save a beer from being permanently pouring pitchers of foam. Just make sure to keep the CO2 off from your regulator to the keg during this process, so you don’t waste excess CO2.
Beverage line:
You will often see this category exclusively referred to as your line length, but that is only half true. The width of your beer line is also an important factor. The goal of these set widths and lengths are to create the right amount of restriction to keep the infused CO2 inside your liquid. The most common size of beer line is 3/16 in inner diameter, 7/16 in outer and is the industry standard for all shorter line runs. If you are going from a basement to a tap upstairs (ie. a run length of 20+ feet) theKOMOS have an Evabarrier 4 mm tubing that allows you to have a shorter line length due to its smaller interior diameter, but these require specialized fittings on both sides of your system, so if you are not set up for it it may not be the right decision to switch to.
Here is a calculator that I like to use that gives you all the variables that can go into changes in your line leangth, but for myself and what I recommend at my elevation of about 5000 feet, I have the best results with a 10 foot beer line of 3/16 in inner diameter vinyl beer line tubing.
Blockages:
If you feel confident that your temperature, pressure and beer line are all right where you want them to be, and you’re still getting foam, you will want to investigate the path that the liquid follows through from keg to glass. Essentially, you would like to minimize any turbulence there may be along the route.
The most common issue I’ve seen is gunk in the lines. If you don’t keep up regular cleanings of your system, you can slowly get buildup inside all the components. Make sure to occasionally do a full disassembling instead of just a clean-in-place (CIP) every now and then, so that you can scrape away any excess buildup. These will generally be seen inside the probe of the coupler, the narrow holes of your tower shank, or throughout the center of your faucet. Take apart all the components you can give them a deep soak in a cleaner like PBW and scrub them with a brush. For the harder to reach areas a line cleaning brush like this one can help get around corners and all the way down through your tubing.
Another common blockage I alluded to earlier is ice crystals. Your beer line is the thinnest portion of your draft system, and ergo the first place that will begin freezing should temperatures drop too low. If your beer line is sitting against the back wall, you may not get any flow at all out of the tubing when it freezes solid, and need to crunch up the lines like a glow stick in order to get it to pour. If the freezing is more slight, it may just be adding chunks into your line that will add turbulence until the ice is melted. Put a thermometer inside your kegerator and make sure your beer lines aren’t directly against any cooling units.
The third most common blockage I see is people using splicers to increase their line length to get to the 10 foot mark I mentioned before. However, these slicers can often cause more problems than they solve. While the width of the splicer when inside the line seems negligible, it can have negative effects and occasionally even introduce air if not tightened properly. Skip these slicers and buy a fresh ten foot line and save yourself a hassle.
