When it comes to choosing the best line for CO2, there are a few factors to consider. The most important factors are the temperature at which you are serving the beer and the length of the beer line.
For most beers served at a temperature of 36-40°F, a keg pressure of 12-14 psi, and a typical serving pressure of 10-12 psi, a 3/16″ beer line is usually sufficient. This size allows for a good balance between flow rate and resistance, resulting in a smooth pour without excessive foaming.
The length of the beer line is also crucial in maintaining the right serving pressure and preventing foaming issues. In general, a beer line length of 6-8 feet is recommended for the aforementioned conditions. This length helps to create enough resistance in the line, allowing carbon dioxide to properly dissolve into the beer and preventing overcarbonation.
However, there are cases where longer beer lines may be necessary. For example, if you have a setup where you need to run the beer line from a basement kegerator to an upstairs tap, the increased vertical distance may require a longer line. In such situations, using a 1/4″ beer line instead of 3/16″ can help maintain the desired serving pressure and minimize foaming issues.
Using a larger diameter line reduces the resistance in the system, compensating for the extra distance and height. This ensures that the carbonation level remains consistent and the beer pours smoothly without excessive foam.
In my experience as a sommelier and brewer, I have encountered situations where the wrong line size or length resulted in foaming issues or undercarbonation. It is crucial to find the right balance between line diameter and length to achieve optimal serving conditions for your specific setup.
To summarize, for most beers served at 36-40°F with a keg pressure of 12-14 psi, a 3/16″ beer line of 6-8 feet is usually sufficient. However, if you have a setup with longer distances or higher vertical heights, using a 1/4″ line may be necessary to maintain the desired serving pressure and prevent excessive foaming. Ultimately, it's important to experiment and fine-tune your system to find the best line size and length for your specific setup.