Here is a system that will quickly chill wort, plus make hot and warm water for post-brew cleanup, saving time and hassle on brew days. Many immersion chillers have their coils stacked directly on top of each other. The resulting metal-to-metal contact does not help transferring heat from the wort to the coils. This interleaved dual-coil design separates the coils, so each coil has maximum contact area with the hot wort.
The two coils are made of 3⁄8-inch soft copper pipe. The inlets and outlets are joined and connected to 1⁄2-inch copper pipe. The larger inlet and outlet pipes are needed because they carry the combined flow of both coils. Due to the fact that the volume of water a certain pipe can move is measured by squaring the radius of the pipe, we can easily calculate that 1⁄2-inch pipe will be able to move almost twice as much water as each individual 3⁄8-inch pipes.
Copper is the ideal material for the chiller. It has excellent heat transfer properties and is easy to cut and solder. I suggest that you shop for copper at plumbing supply vendors. Their prices can be up to 50% less than most home improvement centers.
This rib-cage immersion chiller design can chill a 5-gallon (19-L) batch in 10-15 minutes. Initial chilling is done by recirculating from a 5-gallon (19-L) bucket of tap water. After several minutes, I will switch to recirculating ice water from an insulated cooler, which quickly brings wort to pitching temperature. The resulting hot and warm water is saved for use during post-brew cleanup. An inexpensive water transfer pump is used to recirculate the water. The Drummond 1⁄10 horsepower model is available for about $55 (USD). It comes standard with water hose connections. Using the cooling power of ice eliminates any limitations associated with ground water temperature. Since the system is self-contained, you are not limited to brewing near a cooling water supply.
To use the system, fill a 5-gallon (19-L) bucket with tap water, and an insulated cooler with 5 gallons (19 L) of water and about 20 lbs. (9 kg) of ice. Shop around for ice because prices vary greatly. I get 20 lbs. (9 kg) of crushed ice for a little more than $2. Worth every penny! Heat transfer from ice is dependent on surface area, so the greater surface area of small cubes or crushed ice will give the best results.
Cleanup time for this system is negligible, since water (not wort) is being pumped. The immersion chiller can be dunked and washed off in the insulated cooler (which will be full of warm water after use). There is no need to clean the pump or hoses because they are only exposed to clean water. There are no worries of residue building up inside the pump, hoses, or chiller (as is a problem with plate chillers, for example), because you are moving water, not wort. The pump and hoses are easily stored inside a 5-gallon (19-L) bucket.
Materials & Tools
-Drummond 1⁄10-HP pump #63317
-50 ft. (15.2 m) 3⁄8-inch O.D. soft copper pipe
4 ft. (1.2 m) 1⁄2-inch I.D. hard copper pipe
(4) 1⁄2-inch copper T joint
(2) ½-inch x 1⁄2-inch copper 90 degree elbow
(2) 1⁄2-inch x 1⁄2-inch copper 45 degree elbow
(4) 1⁄2-inch x 3⁄8-inch copper reducing coupling
(4) 3⁄8-inch x 1⁄4-inch copper reducing coupling
(2) 1⁄2-inch copper male threaded fitting
(2) Threaded hose adapter
6-inch (15-cm) spring clamp
Solder, soldering flux, Teflon tape