Why You Have Foamy Beer


The most common problem with draft beer is its propensity to be foamy beer. When a third or more of each glass is foam you're likely losing patience with draft beer.

Before you give up on draft beer and stop using your Kegerator , let's break down the problem and give you some solutions.

Whenever beer is foamy it’s 95% certain that there is a temperature problem. Most beer is carbonated to a level that requires it to be sold cold because cold beer (or any liquid) can hold more dissolved gas. In the case of beer that gas is carbon dioxide. (Learn more about carbonation). So when you have foamy pours coming from your kegerator the first thing to do is look for warm temperatures in your system. The other 5% of foam problems are caused by mechanical issues.

Before we go on to the diagnosis of the problem, let's confirm that the beer is being poured correctly. Improper pouring technique can cause foam. Also, make sure that your keg has had enough time to cool down in the kegerator and settle before you start pouring. A keg can take a day to cool down after transporting it home depending on the time it takes to get it home – and if it had just been delivered to the beer store off the beer truck.

1. Often improper pouring technique is responsible for foamy beer. Make sure that: you are opening the faucet with one quick steady motion. A draft faucet should be fully closed or fully opened. Unlike the kitchen or bathroom faucet, you shouldn't try to control flow by only partially opening the faucet or opening it too slowly.

2. Use clean, unfrozen glasses with smooth inside surfaces. No foam cups, frozen mugs, dirty or soap film on the glasses. Learn more about glassware for draft beer

3. The mouth of the glass should be held just below the faucet mouth, not touching it. Your glass should be held at a 45 degree angle and then brought to the upright position as the glass fills up past the halfway point.

Now that we've confirmed that you're pouring correctly get two pint glasses and in succession attempt to pour two beers. Based on the descriptions below decide which best describes what happened:

The first glass was nearly all foam, but the second glass was successful. If this is the case, start at step 2 below:

Neither pour was acceptable, foam was 50% or more of each glass. If this is the case, start at step 1 below:

The pour exploded into both glasses very fast and all foam. If this is the case, start at step 4 below.

1. Fill a pint glass with tap water and set it on your kegerator floor overnight then take the temperature of that water in the morning using an immersible thermometer.

What's the temperature? Is it under 40 degrees? If so the bottom of of your keg is cold enough. This is the same region of the kegerator where the beer is served from (since the beer is pushed up from the bottom of the keg). See the Anatomy of a Keg to learn more. Do not use an air temperature thermometer such as an oven thermometer. These are not accurate enough. Also, you are interested in liquid temperature only. If your glass of water is not cold enough, your kegerator is not cooling the beer down sufficiently. Here's more information.

2. Fill a pint glass with tap water and put the glass of water on top of the keg or otherwise arrange the glass so that it is near the top of the box. Leave it there overnight and then take the temperature. This is the temperature of the beer lying inside your beer line above the keg up to the hose exit to the tower. Is this temperature under 40 degrees? If so your exiting temperature is cold enough. Cooling your draft tower will correct your foam problem. If not, you have a temperature problem in the top of the box. You need to improve cold air circulation inside the keg box.

3. Dump the cold water out of the glass and pour beer into the glass from the faucet. Dump this beer in the sink or chug it if you want. Now pour a fresh beer into the same glass. Take the temperature of this beer. Is it under 40 degrees? If so, your beer is cold enough. Drink the beer because you don't have a temperature problem. See step four below to solve your foam problem.

4. Can't get enough beer into the glass to take a temperature at all because its all foam? Complete steps one and two above to confirm the proper temperature inside your box. Now disconnect the keg coupler from the keg and take a rough measurement of the length of your beer line.

Measure from the keg coupler to the entrance to the tower, then measure the tower and add the two measurements. In most cases you should have five or six feet of line. If it is less than this, there is not enough resistance in your draft system , which can cause wild pours. If your beer line is the proper length, see step five below for adjusting your gas pressure properly.

5. Look at the outbound gauge on your gas regulator (you may have two gauges; you want the one with the low pressure readings), or the secondary regulator if you are using one. Depending on your beer style the gauge should be reading 10-14 PSI. If it is higher than this, it is most likely too high unless you are dispensing beers like hefeweizens or your beer line is more than six or seven feet. Make sure the gauge is working properly by uncoupling the keg and engaging the pressure relief valve on the coupler. The free flowing gas should noticeably bring down the gauge pressure while the relief valve is open. If not the gauge may be faulty, but it is replaceable. Or the regulator may need to be disassembled and cleaned. Also, if the gauge pressure goes up after you've set it, the regulator may need to be disassembled and cleaned.

Learn More About Gas Regulators
Mechanical Reasons for Foam
Learn More About Gas Pressure

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