A thin disk of foam is the perfect way to top off a draft beer. It’s not so nice when three-quarters of your glass looks like a bubble bath. So when your kegerator beer is too foamy to drink, you’re going to want a solution fast. We’ve scoured the web for tips from savvy homebrewers to explain why your beer is turning to fluff. 

Make sure you’re pouring right. Start with the glass at a 45-degree angle and shift it upright halfway through. Then check the temperature inside your kegerator. You might need to calibrate the thermostat or add a fan. Next, see if the beer lines are too short, too dirty, or hanging below the top of the keg. Finally, consider adjusting the CO2 pressure in the keg.

If you want to get back to pouring clean, crisp drafts, then dive right into our guide!

Foam, Physics, and Fermentation

There are a few reasons why a draft can come out foamy, but they all come down to temperature and pressure. The yeast cells that ferment your beer breathe out carbon dioxide, or CO2, as they work. The high-pressure environment of the keg keeps this gas dissolved inside the liquid.

But gases like to move from high to low pressure. Once the beer gets outside the keg, the CO2 packed inside heads toward the open air where it has room to stretch out. As each bubble rises to the surface, it picks up a coating of water-repelling material left over from your malt and hops. That’s what creates the fluffy, creamy mat of foam that floats on your beer. 

So what makes the difference between a nice head of foam and a glass that’s mostly bubbles? It usually comes down to how cold the beer is and how high the pressure is in your keg. More carbonation pressure means more foam, and warmer temperatures increase that pressure.

Now that we’re clear on the basics, let’s review some specific problems that can make for too much foam.

7 Reasons Your Kegerator Beer Might Foam Too Much

#1: Poor Technique

There’s an art to the perfect pour. You might need to work on your technique if you’ve been bottling your brews and you’ve just switched to kegs. Pouring the wrong way can create too much foam even if your kegerator setup is perfect. 

First of all, give your keg some time to cool. It won’t be ready to serve the minute you pop it into the kegerator.  It will take at least 24 hours to get cold, and depending on how big it is, it could need as long as three days.

Make sure you’re using a clean glass! Any greasy residue causes extra fizz to form on the sides. The temperature matters, too. A chilled glass is good; a frozen one makes for more foam. 

Hold your glass at a 45-degree angle to the tap when you start pouring. Once it’s about halfway full, shift it to a vertical position as it fills the rest of the way. Stop pouring when it’s a little shy of the top. Beer aficionados disagree about how big of a head a draft should have, but most shoot for a half-inch to an inch thick.

Man pouring glass of beer and making too much foam
If the beer comes out too foamy, pay attention to your technique.

#2: The Bottom of the Keg is Too Warm

When the temperature of the beer you’re serving is too high, the CO2 inside will be much more eager to escape. Since your tap draws beer from the bottom of the keg, you should check the lower part of the cooler first. Set a glass of water on the floor inside your kegerator and leave it there for a few hours. Then measure it with a food thermometer

Does it match the temperature on your thermostat? That’s good – it means you don’t have to adjust your temperature control system. As with head size, beer snobs tend to argue about the perfect serving temperatures for various brew styles. Try to keep it to 45 degrees Fahrenheit or less if you’re aiming to reduce foaming.

If the thermostat isn’t doing its job, you may need to calibrate it. Unplug it and turn the temperature setting as high as it will go. Then grab a small screwdriver and detach the thermostat from your kegerator.

Find the temperature range screw. You’ll usually have to take off the knob and the faceplate of the thermostat to get at it. Once you find the screw, give it a quarter-turn in the clockwise direction. This should tighten up the spring inside and lower the temperature range.

Plug it back in and give it a full 24 hours to get to the right temperature, then measure again. You’ll probably need to adjust it a few times to get to the right range.

#3: The Temperature is Uneven

Sometimes a refrigeration chamber that’s cold enough at the bottom can still be too warm near the top. This can cause your kegerator to start spitting out foam halfway through a keg. That’s because the beer in the upper part isn’t getting cool enough by the time it hits the tap.

The solution is to get the air moving around inside with a recirculating fan. If you have a way to run a power cord out from the kegerator, you can plug a wired fan like this one right into the wall. Or, if you know how to hook up wiring, you can splice the fan into the power supply for your thermostat.  

#4: Warm Beer Lines

What if the first pint or two that you draw every night comes out as a mess of foam, while the later ones are fine? This is a common problem with a simple solution. 

What’s happening is that the beer sitting in the hose is warming up while you’re waiting to serve it. Your beer lines run up from the keg, and since warm air rises, they tend to heat up. Your beer lines extend up from the keg into the draft tower, and since warm air rises, they tend to heat up. 

This effect is stronger if the lines are inside a hollow draft tower that sticks up from your kegerator. Because the tower is outside the refrigeration chamber, it doesn’t get as cold.

Your circulating fan will help a bit, but it works even better if you add a length of hose to push the cold air directly into the tower. Or you could buy a blower fan with an attached hose from a kegerator supply store.

#5: Short Beer Lines

Temperature isn’t all that matters when it comes to your beer lines. The longer they are, the more your brew depressurizes on its way to the tap. A good rule of thumb is to use 7-10 feet of 3/16” vinyl tubing

That’s assuming you’re keeping your beer at about 12 PSI, which is the default setting for most casual brew fans. The exact length changes depending on:

  • The density of your beer
  • The height of the tap above the keg
  • Your altitude
  • How fast you want the beer to come out of the tap
  • The temperature
  • The CO2 pressure inside the keg

Luckily, you can find online calculators to do most of the math for you. This one includes typical density ratings for different styles of beer.

You should also make sure that the extra length in the line stays coiled on top of the keg. If some of it is hanging below the upper edge, you could get air in the lines, creating hiccups as you pour.

We hope this goes without saying, but please clean the lines regularly. If grime builds up in there, it can make your beer fizzier on its way up from the keg. It’s best to replace them every so often too.

Kegerator Beer Lines
Draft beer line is the essential part that carries your kegerator beer from the keg coupler to the draft faucet.

#6: Coupler Mismatch

The coupler is the part that links the valve of your keg and the gas line from your CO2 tank. But not every combination of keg and coupler is a match made in heaven. Different keg types fit different couplers. You might still be able to tap a keg with the wrong coupler, but it tends to cause an uneven flow of gas. This can over-foam your beer.

Check which type of coupler and keg you have. Most American-made brands use the Sankey D coupler style, but it’s always good to make sure.

#7: High CO2 Pressure

Is your beer still foaming after you’ve tried all the suggestions above? You might be putting too much pressure on it. 

The proper CO2 pressure in the keg depends on the type of beer you’re serving. Use this handy chart to figure out the right level for your brew. If you need to take some pressure off your keg, there are two methods you can use.

The standard technique is to change the setting on your CO2 regulator using the dial or screw. Then switch off the regulator, and vent the excess pressure using the release valve on the keg coupler. Now turn the regulator back on. Wait an hour or two and repeat. You’ll usually have to do this a few times to get to the right level. 

There is a faster way, though! Depressurize your keg, then hook up your CO2 line to the output fitting instead of the input. Give it a quick burst of gas, only about one second long. Then let the pressure out little by little using the relief valve on the keg lid. 

You might have to repeat this method a few times as well, but it only takes around 20 minutes as opposed to a few hours. This trick works by knocking CO2 out of suspension by pushing bubbles out through the tube in the bottom. The result is a less carbonated beer.

Conclusion

Excess foam is a waste of good beer. That’s why it’s so important to understand the balance between temperature and pressure that controls carbonation. Make sure your brew is cold enough and the lines are long enough that the CO2 isn’t bursting out of the solution when you pour. Then check whether you’re over-carbonating the keg. 

With a few simple adjustments, you’ll be pouring beautiful pints every time. Raise a glass for us if this guide helped! Thanks for reading, and don’t hesitate to visit us again if you have other questions about your home bar setup.