I built my counterflow chiller out an old garden-hose, some flexible 3/8″copper tubing and various odds and ends. I already had the hose, the pipe and some of the fittings laying around. The major purchase for me was the 3/8″copper tubing. If you have a copper immersion chiller you could scavenge the tubing to convert it into a counterflow. You're going to find most of the other parts and supplies you need on the plumbing aisle.
NOTE: I used 1/2" copper pipe and fittings. You could substitute 1/2"PVC and it would work just as well. It's cheaper and you won't need to solder anything.
25' garden hose
25' of 3/8" ″OD copper tubing.
1' of 1/2" copper pipe
2ea. 1/2" copper tee fittings.
2ea. 1/2" copper female
2ea. Brass compression fittings for 3/8" copper tubing
4ea. Hose Clamps
Tie Wraps (AKA Zip Ties)
Hacksaw or Tube cutter
3/8" Drill Bit
I started by building the two end assemblies. Cut six pieces of 1/2" copper pipe about 1 1/2" long using a hacksaw or tube cutter. The pieces can be a bit longer or shorter, you don't need to be precise. Use the sandpaper to 'shine' the inside of the fittings and the outside of the pipe sections. Home Depot will be happy to sell you special little tools to do this, and they're not expensive. After you've shined the surfaces to remove oxidation, apply flux and sweat (solder) the joints.
The copper compression fittings are the standard pieces you may have under your sink. When they're used in your house, the 3/8" tubing goes only part way into the fitting. We're going to want the tubing to go all the way through, so we need to use the 3/8" drill to remove the internal stop. Please, DO USE a vise to hold these little parts while you're drilling. Things can get rather unpleasant when your holding small parts with pliers if the drill bit binds.
|Drilled out on the left, original on the right.|
Cut the last several inches off both ends of the garden hose. The flexible 3/8″copper tubing is probably in a coil. Straighten it out as much as possible and shove it inside the garden hose. Slide one of the hose clamps over each end of the hose, then slide one assembly over each end 3/8″tubing until you can shove an inch of the copper pipe from that assembly inside the hose. Secure with a hose clamp, and tighten the compression fitting around the 3/8″copper tubing. Wrap the whole thing around something round. I used a Corny Keg. Tie-wrap the layers together to prevent your wort chiller from acting like a Slinky when you lift it. Slide one of the hose clamps over each of the little end pieces of the hose, jam the hose over the copper pipe coming from the sides of the two copper tees, and secure the hose clamps. You're done!
When your wort chiller is complete, connect it to your garden hose, and slide 3/8″ ID flexible tubing over the 3/8″ copper tubing tubing in a line between your boil and your fermenter. Hook it up so that the assembly that has the outgoing wort is on the same end as incoming cold water.
I added a thermometer to mine so I could monitor the outgoing wort temperature. I had to add a bunch of brass compression fittings on the end to make that work. Normally, the cool wort would come out where the thermometer is, rather than out of a tee'd connection.