Foam from kegerator

[Wfu1bunn]

Trying to figure out how to reduce foam when pouring a beer from my kegerator. Temp in kegerator is around 32 degrees; beer lines are 4 ft long; just cleaned my lines and faucets but still get too much foam.

Any ideas on what to do?

 

[kh54s10]

Trying to figure out how to reduce foam when pouring a beer from my kegerator. Temp in kegerator is around 32 degrees; beer lines are 4 ft long; just cleaned my lines and faucets but still get too much foam.

Any ideas on what to do?

Usually the answer is longer lines. Usually 10 feet is the norm.

Pressure is also another consideration. 8-12 pounds is normal. There is some difference with temperature also. 32 seems really cold, maybe set things in the low 40s??

 

[doug293cz]

Usually the answer is longer lines. Usually 10 feet is the norm.

Pressure is also another consideration. 8-12 pounds is normal. There is some difference with temperature also. 32 seems really cold, maybe set things in the low 40s??

This ^^^

Brew on

 

[Drewtattoo]

I changed my brew lines from 1/4" ID to 3/16" ID and have reduced foam dramatically. My lines are only 8 feet as well.

 

[m00ps]

If your lines are only 4 feet long I dont think there is any reasonable way to not get +90% foam. Even if you somehow hooked up like 2/16" tubing (do they even make that), I think youd still be getting foam at 4 feet

 

[Drewtattoo]

Go to 3/16 ID tubing, 8-10 feet. It works great for me @ 38-40F.

 

[DrinksWellWithOthers]

There are several things that can cause your beer to foam. The most common suspects are temperature and system imbalance. Temperature does play a role in balancing a system however I like to also address it individually as there are several times where a system is set up correctly but the temperature of the beer is affected by elements outside of balancing applied pressure versus restriction.

You state your kegerator temp is around 32F but what temperature is the beer? Ideal keg beer temperature is 38F but while it may be 38F in the keg it may not be by the time it hits the glass. Pour a pint and check the temperature of the beer. If its ~38F then you're OK, but if its warmer then you need to find where its heating up and in most cases its further up the line close to the faucet in a tower or in the collar area of a keezer. In a commercial setting long draw systems use glycol lines that run alongside the beer lines and actually touch the shank on the back of each faucet to ensure the beer is cold its entire length of travel. For direct draw units like kegerators there is likely a blower fan with a hose that runs up the tower pointing towards the shanks and cooling the entire tower as the cold air sinks. There are many methods to keeping lines cold on this forum but I'm a fan of the blower motor method.

Now if the temperature of the beer is 38F coming out of the faucet then its possible your system is out of balance.

By balancing a draft system we want to apply appropriate pressure (CO2) to the beer to push it out of the keg and through the lines while against the restriction based upon it by certain variables (ie: gravity, specific hardware, and tubing) all while maintaining the desired carbonation level. Basically we want to make the combined restriction of all the parts of your draft system the same as the applied pressure coming from your regulator.

So what do we need to know?
1. CO2 volumes of the carbonated beer. Most craft beer is around 2.4 volumes.
2. Temperature of the beer. We're shooting for 38F.
3. The CO2 equilibrium pressure given these 2 numbers on a carbonation chart. I use the one supplied by the Brewers Association. Its available online but I'm using my book. These charts are found in the appendix in the back. For practice sake, lets use 2.4 vol at 38F. According to the chart the required PSI is 10.3. Now always round up the next whole number and add 1. I wish I could tell you why to add one but I honestly don't remember right now. So that gives us an applied pressure of 12.

Now that we know the beer requires an applied pressure of 12psi on the pressure side, we now need to balance the rest of the system on the beer side. For that we need:
1. "Lift" or height of the faucet to the bottom of the keg. This distance applies a resistance of 1/2 psi per foot. Most kegerators are around 4 ft so 4 x .5 = 2.
2. Any hardware including shanks, couplers, etc. In most cases we will apply a resistance of 0 psi if this is a regular set up. Restriction values are placed when using bent metal tubing and choker lines.
3. Tubing ID will play a huge factor here and will determine the amount of line you need. 3/16" ID vinyl tubing applies a restriction of 3 psi/ft.

Now let's go back to our applied pressure of 12 from above. We have a combined restriction of 2 so far. 12 - 2 = 10 psi which we need to account for with tubing. 3/16" vinyl tubing has a restriction of 3 psi/ft so 10/3 = 3.333 which is about 3' 4" of tubing. If you want to use 1/4" vinyl tubing which has a restriction of .85 psi/ft we'll take that 10 psi again and divide it by .85 which gives us 10/.85 = 11.76 which we can round to 11' 9" of tubing

Other factors that will cause a beer to foam are dirty beer lines and faucets, kinked beer lines, loose connections, a leak or puncture in a beer line (most likely near hose clamps), broken couplers (ball lock connectors) and broken faucets. All of these will cause nucleation points for CO2 to come out of solution and create foam.

I'm in the middle of a brew day and going back and forth to my laptop and recalling as much as possible from memory so I hope this is correct and coherent.

 

[hvjackson]

[...]

By balancing a draft system we want to apply appropriate pressure (CO2) to the beer to push it out of the keg and through the lines while against the restriction based upon it by certain variables (ie: gravity, specific hardware, and tubing) all while maintaining the desired carbonation level. Basically we want to make the combined restriction of all the parts of your draft system the same as the applied pressure coming from your regulator.

So what do we need to know?
1. CO2 volumes of the carbonated beer. Most craft beer is around 2.4 volumes.
2. Temperature of the beer. We're shooting for 38F.
3. The CO2 equilibrium pressure given these 2 numbers on a carbonation chart. I use the one supplied by the Brewers Association. Its available online but I'm using my book. These charts are found in the appendix in the back. For practice sake, lets use 2.4 vol at 38F. According to the chart the required PSI is 10.3. Now always round up the next whole number and add 1. I wish I could tell you why to add one but I honestly don't remember right now. So that gives us an applied pressure of 12.

Now that we know the beer requires an applied pressure of 12psi on the pressure side, we now need to balance the rest of the system on the beer side. For that we need:
1. "Lift" or height of the faucet to the bottom of the keg. This distance applies a resistance of 1/2 psi per foot. Most kegerators are around 4 ft so 4 x .5 = 2.
2. Any hardware including couplers, shanks, bent metal tubing, etc. In most cases we will apply a resistance of 3 psi.
3. Tubing ID will play a huge factor here and will determine the amount of line you need. 3/16" ID vinyl tubing applies a restriction of 3 psi/ft.

Now let's go back to our applied pressure of 12 from above. We have a combined restriction of 5 so far. 12 - 5 = 7 psi which we need to account for with tubing. 3/16" vinyl tubing has a restriction of 3 psi/ft so 7/3 = 2.333 which is about 2' 4" of tubing. If you want to use 1/4" vinyl tubing which has a restriction of .85 psi/ft we'll take that 7 psi again and divide it by .85 which gives us 7/.85 = 8.23 ft which we can round to 8' 3" of tubing.

[...]

This is a very rigorous way of arriving at a length of beer line, but I don't think it is validated by real-world experience. I carb my kegs to 12 psi and need at least 5 ft of 3/16" line, not the 2'4" you've calculated. I don't know anyone who has that short of a line.

In my opinion a good rule of thumb is to start with 6' of 3/16" line and see how it goes. There's not really any problem with tubing that is too long, it will just pour more slowly.

Factors that require a longer line:
- higher keg pressure
- larger tubing

Factors that require a shorter line:
- faucets are significantly higher than kegs
- many restrictions /fittings in the line

 

[DrinksWellWithOthers]

This is a very rigorous way of arriving at a length of beer line, but I don't think it is validated by real-world experience.

I work in the industry and use this in the trade. It is the method taught by Micromatic in their Advanced Draft Training class.

 

[DrinksWellWithOthers]

This is a very rigorous way of arriving at a length of beer line, but I don't think it is validated by real-world experience. I carb my kegs to 12 psi and need at least 5 ft of 3/16" line, not the 2'4" you've calculated. I don't know anyone who has that short of a line.

In my opinion a good rule of thumb is to start with 6' of 3/16" line and see how it goes. There's not really any problem with tubing that is too long, it will just pour more slowly.

Factors that require a longer line:
- higher keg pressure
- larger tubing

Factors that require a shorter line:
- faucets are significantly higher than kegs
- many restrictions /fittings in the line

I realize I made an error and used a value of 3 instead of 0 for hardware restriction. This changes the length of 3/16" ID tubing to 3' 4".

You are right about the previous length being too short but this is how draft systems are balanced.

 

[day_trippr]

"3/16" vinyl tubing has a restriction of 3 psi/ft"

Not at the volumetric flow rates and fluid viscosities pertinent to dispensing beer.

That oft repeated canard is the reason why 99% of calculators are wrong.

Fortunately, there is one that is right.

Cheers!

 

[PapaO]

Trying to figure out how to reduce foam when pouring a beer from my kegerator. Temp in kegerator is around 32 degrees; beer lines are 4 ft long; just cleaned my lines and faucets but still get too much foam.

Any ideas on what to do?

How did you carb your beer? Is 32 Beer temp or kegerator temp? What is your Co2 PSI?

This is the classic I have foam post and why all line length calculators are wrong to 99% of I have foam posts on HBT. So let’s see where this post goes.