A glycol power pack is the refrigeration unit at the heart of a long-draw draft beer system. If your kegs sit more than about 25 feet from the taps, you need one to keep beer cold the whole way to the faucet. Here is how it works and when you need it.
What it is
A glycol power pack (also called a glycol chiller) is a compact refrigeration system with four key parts: a compressor, an insulated bath of food-grade propylene glycol and water, one or more circulation pumps, and the connections to your trunk line. It chills the glycol bath and pumps that cold fluid out to the beer.
How glycol cooling works
Inside an insulated trunk line, glycol lines run bundled tight against the beer lines. The power pack pushes cold glycol out to the tower and back in a continuous loop, pulling heat out of the beer along the entire run. Because the glycol stays in direct contact with the beer lines the whole way, the beer arrives at the faucet within a degree or two of your walk-in temperature. The glycol never mixes with or touches the beer.
Why long-draw systems need one
In a short direct-draw setup like a kegerator, the beer travels a few feet and stays cold on its own. On a long-draw system, beer sitting in an uncooled line warms quickly, and warm beer pours foamy and flat and wastes product. A glycol power pack is what makes long runs, multiple towers, and remote keg rooms possible without sacrificing pour quality.
Power pack vs. other cooling
Air-blower systems push chilled air down the trunk line, but they lose effectiveness past short-to-medium runs. Glycol holds temperature far better over distance, which is why it is the standard for commercial bars, breweries, and stadiums.
Choosing and sizing one
Power packs are sized by run length, tap count, and cooling type. See our guide to sizing a glycol chiller, compare air, water, and remote cooling, browse commercial glycol chillers and power packs, or talk to a specialist.