DIY Beer Line Cleaner

I found this DIY Beer Line Cleaner in the BrewBoard a couple years ago. This is a pretty handy and inexpensive gadget for cleaning your keg lines. Cleaning your beer lines is important to avoiding off flavors and for an overall happy draft system. I usually clean mine every time I swap kegs and/or before we have company over. I haven't seen much documentation regarding this trick, so I thought I'd do a little write-up on it. You'll need the following:

(1) Carbonator Cap

(1) Empty 2 liter plastic pop bottle

(1) Flat file, sand paper, or some other abrasive

A Carbonator Cap is a ball lock fitting valve that replaces the cap on a 2 liter soda bottle. It's intended to pressurize the pop bottle so that you can transport your homebrew with minimum loss of carbonation. They're available through most LHBS and online. Prices vary but you should be able to find them for $15 or less.

You'll have to make a slight modification to the Carbonator Cap to use it as a beer line cleaner. Gas posts are slightly larger in diameter than liquid posts. Gas QD's can fit liquid posts, but liquid QD's can't fit gas posts. In order to be able to connect both gas and liquid QD's to your Carbonator Cap you'll have to slightly reduce the diameter of the post. You don't need to remove much material...just enough so the liquid QD will fit. I used a mini flat file and made a couple passes around the outside of the post.

1. First, carefully removed the O-ring.
2. Grab your abrasive of choice and remove some of the material from the post. Try to keep the pressure consistent so you remove material evenly all the way around the post. Test after each revolution and stop when the liquid QD fits snugly.
3. Clean off any residue and reinstall the O-ring.

Below is a close-up of the section where you need to remove material.

When you use this as a beer line cleaner, you'll do the following:

1. Fill the pop bottle with a cleaning solution (mixed per the manufacturer's instructions) and cap it
2. Pressurize the pop bottle with CO2 using the gas QD. I usually fill mine with one quart of cleaning solution and pressurize to 12 PSI. Remove the gas QD.
3. Attach the liquid QD for the beer line you intend to clean and invert the pop bottle.
4. Open the tap until the cleaning solution pushes out any remaining beer and flows clear.
5. Close the tap and let it sit for about 10-15 minutes. Repeat for the rest of your taps.
6. Thoroughly rinse out your pop bottle with clean hot water. Pressurize it as above and use the hot water to flush the cleaning solution from each of your lines.
7. I usually follow up the hot water flush with a sanitizer flush, but this is optional.

That's all there is to it.