Items you will need
- 3/8 inch vinyl tubing
- 1/4 inch copper tubing
- Tube bender
- Zip ties
- 3/4 inch pipe insulation
- Duct tape
- Small aquarium pump
- 2 gallon bucket
- 1/2 inch female pipe thread to 3/8 inch hose barb adapter
- 3/8 inch hose clamps
A common cause of unwanted foam in draft beer is when beer has warmed up in the vinyl line between the faucet and the keg. Ideally, that beer line should be chilled. Forced cold air is the most common method of chilling the beer line in a home draft system; however, a liquid chilling system offers much better performance. A complete commercial glycol chilling system is likely not a realistic option for a home draft system, but it is possible to create a simple liquid-cooled system using water chilled by your beer fridge.
Run the 1/4 inch copper tubing alongside the existing beer line, securing the two lines together using zip ties. Any beer line not in the main part of the fridge must have copper tubing running alongside it. If the layout of the draft system requires that the copper tubing be bent, be sure to use a tube bender, otherwise the tubing will likely kink.
Copper is a much better conductor of heat than any flexible tubing, which will enable the cold water to cool the beer much better. For that reason, the cooling line must be made of copper, despite it being harder to work with.
Wrap the pipe insulation around the copper and beer line bundle, being sure all of the copper line is covered. Wrap the bundle tightly in duct tape.
The copper line must be insulated to keep it from warming up due to the surrounding warmer air. All cooling potential must go to cooling the beer line.
Connect the output of a small aquarium pump (usually 1/2 inch male pipe thread) to a 3/8 inch hose barb. Connect one end of an appropriate length of 3/8 inch vinyl tubing to the hose barb, and the other end to the copper tubing used in Step 1. Secure the connections by tightening 3/8 inch hose clamps over the ends of the vinyl tubing.
Connect 3/8 inch vinyl tubing to the other end of the copper tubing, again securing with a 3/8 inch hose clamp. The tube must be long enough to reach the reservoir, and will act as the return tube, to bring the water back to the reservoir.
Place the aquarium pump in a bucket or other appropriate reservoir, filled with water. The more water the reservoir contains, the better the system will perform. Any capacity above 2 gallons should be fine. Put the reservoir in your beer fridge.
Plug in the power cord of the pump. Verify there are no water leaks in the system. If there are any leaks, go back and tighten up any offending hose clamps.
If your beer fridge is set at a temperature below freezing, you must keep the system running at all times or the water in the lines will freeze.
Although a brand new aquarium pump from a pet store will work fine, acceptable pumps can often be found for very little money at electronic surplus stores.