What is a Keg Coupler?

Keg Coupler

Now that your home bar or man cave has its own kegerator to cool and dispense that frothy beer you love so much, it would be wise to get acquainted with some of the essential components of your kegerator. One of the most important parts of your kegerator is the keg coupler.

What the Keg Coupler Does

Think of the keg coupler as a “key” and the valve of a keg as the “lock”. They can’t work without each other. The keg coupler attaches to the valve and to a CO2 compressed gas line. It allows the compressed air to enter the keg and push out the beer.

As a result of all of these components working together, you get a perfectly chilled and delicious draft beer in the comfort of your home.

D Coupler
D Coupler
A Coupler
A Coupler
G Coupler
G Coupler
M Coupler
M Coupler
S Coupler
S Coupler
U Coupler
U Coupler

Types of Keg Couplers

This is where it gets a little bit more difficult. Depending on what type of beer style you have in your kegerator, you may need a different type of coupler in order to serve it correctly.

To choose the correct coupler for your home use, you must know the brand/style of beer you serve, know where it was brewed and/or the size of keg it is in. This is because there are six different types of keg couplers. Here is a quick rundown of the different types of commercial keg couplers.

  • D Coupler — Fits U.S. Sankey Keg Valves
  • A Coupler — Fits Most German Keg Valves
  • G Coupler — Fits Some European Keg Valves
  • M Coupler — Fits Some German Keg Valves
  • S Coupler — Fits European Sankey Keg Valves
  • U Coupler — Fits Some European Keg Valves

In order for your beer to be served properly, it needs to have the correct type of coupler that fits the valve on the keg. The type of coupler you need will depend on where that specific beer was kegged.

For example, the American Sankey “D” System coupler is easily the most popular. It fits all domestic brand kegs, as well as 95% of American beers. If that is all you are planning on drinking out of your kegerator, then this would be the coupler you should choose.

If you have any questions as to which type of keg coupler you need, it would be wise to call your local distributor, the store from which you bought your keg or maybe even the brewery itself. For quick reference on the most popular beers, please refer to our handy list of keg couplers needed for different brands of beer.

How to Install Your Keg Coupler

To install your keg coupler to your kegerator, you must first attach the CO2 regulator to the CO2 cylinder. Make sure that the cylinder is filled and the valve is closed. Then, securely pair up the regulator to the CO2 cylinder. Attach the gas line to the “gas out” port on the regulator and secure in place with a clamp. Then, attach the other end of the gas line to the “gas in” port on the coupler. Next, attach the beer line to the liquid out port on the coupler.

Now, you are ready to connect the coupler to the keg. Ensure that the CO2 cylinder vale is in the “off” position and the pull handle of the coupler is in the diagonal/upper position. Find the locking neck on the kegerator, and turn the coupler clockwise 25°. Then, pull out on the handle, push it down into the keg valve and release the handle. This will lock the coupler in place and securely attach it to the kegerator.

With the coupler attached to the keg, slowly turn on the CO2 cylinder. At this point, you will hear gas flowing from the CO2 cylinder and regulator through the keg coupler and into the keg. Pull on the pressure relief valve to allow gas to vent and give you an accurate reading on the pressure gauge, then calibrate the regulator to the recommended serving pressure for your beer. You are now ready to serve your own draft beer.

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Jeff Flowers

About Author

Jeff Flowers has been a self-described beer geek for over a decade now. When he's not chasing his daughter around, you can usually find him drinking a fresh brew and wasting too much of his time on both Google+ & Twitter.


  1. Josh P says

    I was hoping you could answer a question for me. Standard kegerator w purchased beer kegs. When I attach the coupler to the keg, I am getting a small amount of beer that goes into the gas line. Everything is hooked up properly, but I don’t know if I should have an attachment for the gas line that will only allow gas to flow in, but keep things from flowing back towards the regulator. Thanks for any advice.

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