The truth is, it is very easy to flush a line by filling a keg with water and a cleaning agent. You would then hook it up to the tap and Co2 and open up the lines. This however is very wasteful of your Co2, line fluid and water.
Fortunately all the parts you need are at your local hardware and home brew stores to construct a cheap line flusher that uses a hand pump to provide the pressure and a standard liquid keg post to provide the coupling to the keg lines. This is pretty much a hand pumped mini-keg.
The initial design for my keg cleaner came from this post to the homebrewtalk.com forum. I however wanted to use a bigger 1.5 gallon tank with a hose attachment. This necessitated an extra bushing to fit the smaller threads on this model of pump sprayer.
Hardware Store Parts
- Model 1415BC 1.5 Gallon/5.7 Liter Flo Master hand pump sprayer
- A-176 3/8" Flare x 3/8" FIP Watts Coupling
- LFA-778 3/8" MIP x 1/4" FIP Watts Bushing
- Teflon tape
Home Brew Store Parts
- Ball lock liquid post with 3/8" flare
You will usually find the hand pumps in the gardening section among the weed control chemicals. I chose the bleach sprayer so I have the option to use harsher cleaners when needed and the ability to store the cleaners in the container. You may find cheaper versions if needed but make sure you check the threads for a fit. They vary even among different models of the same manufacturer.
The assembly is easy. Follow the directions for assembling your sprayer. Remove the wand attachment from the spray handle. Using Teflon tape, screw the bushing to the handle and tighten with a wrench. Use the same procedure with the coupling and then with the post.
To use simply fill with water and the correct amount of cleaning agent and pump with the hand pump. Have something under the tap to catch the water. You then attach the line to the ball lock post like you would any keg, open up the tap and squeeze the trigger on the pump's handle. The cleaning fluid will flow through your lines flushing them out. Make sure to repeat with clean water to get any lingering cleaning liquid out of the line.
The nice thing about this setup is that you don't have to wait until your keg is empty to flush the lines. If you were away for a week you can flush the line of the beer that was in the tower (which usually sits a bit warmer than the the rest of the keg so is prone to spoilage).
The biggest part of making a good brew is keeping things clean. Hopefully this DIY project can make that process a little bit easier.