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Originally Posted On: https://draftbeerdispense.com/foamy-beer/
Do you have foamy beer issues? If so, the problem is usually related to one of these things:
- Restriction Value ( found in the beer line used)
- Temperature (dispensing beer at 38 F)
- Applied Pressure (Making sure gas pressure equals the restriction value).
This blog post will discuss how to solve foamy beer problems by discussing each possible cause and how to fix it. So you can pour clear beer…not foamy beer.
For a more in depth guide about beer fundamentals check out this post.
Foamy Beer Due to Temperature
In general, beer will foam when it’s served too cold. It will also foam if, and usually the more common issue if it’s too warm. If your keg is stored in an area with a constant temperature, then you need to make sure the temperature of the beer inside is also constant.
Maintaining consistent refrigeration (38 degrees F) is important. One way to check where your beer temps at is by taking a digital thermometer, pouring some beer, and temping it. Where we want to be is 38 degrees. When beer is served warmer it becomes unstable and foams.
The other place to check the temperature is inside the kegerator or beer cooler. Check the temperature by placing a glass of water in there and letting it sit for 24 hrs, then use a digital thermometer to check it.
By checking the kegerator, beer cooler and temping the beer from the faucet you will know if it’s a temperature issue or not. The target temperature for optimal dispensing is 38 degrees Fahrenheit
Using The Wrong Beer Line
If you use the wrong beer line for a kegerator, then foaming can be an issue. In this case, you need to replace your beer line with one that’s appropriate (a standard draft beer line).
Since we are most likely addressing a kegerator. The type of beer line you want to use is a 3/16″ I.D. vinyl line. Typically it will be about 4′ in length and will have a restriction value of 3 lbs per foot. So it will have a total restriction value of 12 lbs.
So what’s important about the 12 lbs of restriction? We want to match the applied pressure from the C02 regulator and the Restriction value from the beer line. This will allow the beer to pour at 2 oz’s per second, and pour clear beer, while maximizing keg yield.
The next question is how do we determine the right length of beer line for our kegerator? In the example, I used 4′, but that can vary depending on the units of carb dissolved in a beer.
Units of CO2 are simply the amount of dissolved CO2 in a beer.
Use the Carbonation Chart to Determine Line Length
Here is a carbonation chart below to show the pressure and restriction value based on the type of beer or units of carb. To use this chart find out how cold your cooler is. 2nd, find out what the beer is carbed at. To find this out exactly reach out to the brewery. On average for most ales and lagers I figure 2.5 volumes of C02, but every beer will vary slightly.
For example let’s say we want to pour a beer carbed at 2.5 volumes of C02 and the temperature of my cooler is 37 degrees. So I would need to apply 11.9 lbs of C02 pressure for my beer to stay in equilibrium. Next we would want to match that value with restriction. 3 lbs per foot in 3/16″ I.D. beer vinyl line. For a total of 4′ would equalize our applied pressure and ensure our beer pours properly.
C02 Chart
Applied Pressure Causing Foamy Beer
If the foaming issue is related to applied pressure, then we need to adjust it. In this case, you want a gas regulator with an adjustable knob or dial so that you can make adjustments. Based on what type of beer being dispensed and its carbonation level
We want to set the applied pressure at 12 lbs, this is what we used in our previous example. The key thing here is that foaming won’t be an issue if you use a regulator with adjustable knob or dial and target setting of 12 psi.
If the applied pressure is higher than the restriction value the user can experience foamy beer. Also, if the pressure is too low it won’t push the beer through the lines properly causing it to foam. This is why it is important to match the restriction value and applied pressure from the gas source.
Other Possible Beer Foaming Issues
Pouring A Beer Wrong
As simple as this sounds. Some bartenders and people don’t know how to pour a beer correctly. You want to hold the glass at a 45 degree angle with the beer faucet just above the glass. Pour the beer till about 3/4 of the way filled. Tilt up to get a good head on the beer and shut off the faucet.
Dirty Beer Lines
Cleaning beer lines is an important part of having a draft beer system. This is recommended every 2 weeks with a caustic clean, and an acid clean every quarter. If the lines aren’t cleaned properly beer stones and dirty lines can cause the beer system to pour poorly. Also, the beer will suffer in flavor and taste.
Warm Keg
Sometimes Kegs are delivered or tapped when they aren’t at 38 degrees. When this happens they will pour foam. Temp the beer from the faucet and if it’s warm. If the keg is warm the best thing to do is 86 it, leave it in the cooler for 24 hours so that it can get back to temperature.
Malfunctioning Beer Equipment
Every once in a while malfunctioning beer equipment can be the cause of foamy beer. Usually, I start at the keg coupler and make sure the jumper line from the coupler to the faucet and shank is full of clear beer.
If there are air-bubble in the line check the gasket inside the beer nut. If it’s not sealed correctly this can cause excessive foaming.
The other piece of equipment to check is the beer faucet itself. Make sure the gasket seal inside the beer faucet is resting correctly and there are no tears in it.
Sometimes kinked beer lines get trapped in between kegs and this can cause excessive foaming. By looking over the dispensing equipment really quick. This will also check off the equipment as the culprit.
Summary
In this blog post, we talked about the main 3 things that are responsible for foamy beer. This is beer temperature, the restriction in the beer line, and the applied Co2 pressure to push the beer through the system.
On top of that, we briefly talked about some other factors that can increase beer foaming from a draft system. Pouring a beer the wrong way, dirty beer lines and malfunctioning beer equipment.
By reading this post someone can figure out how to solve the foamy beer issue and have a great pouring system.
If you have any more questions you can always reach out us here. I encourage you to check out our blog for more draft beer dispensing resources, as well as our recommended products
Cheers!