Making a DIY Wort Chiller

You might’ve heard that the quicker you chill your wort after boiling, the less likely it is for bacteria and other unwanted microbes to spoil it. You might also have heard that an immersion chiller is a common way to quickly cool wort. While there are many low-cost options available to purchase, like the one's sold here on Homebrew Supply, building a DIY wort chiller can be a very fun weekend project.

An immersion chiller is a basic heat exchange system. A coil of tubing (typically copper) with cool water flowing through it is immersed into your hot wort. The hot wort warms up the cold water, which when pumped back out, removes heat from the system and eventually cools your wort.

First-F

If you’re lucky to live in an area with cool ground water (~50F) then you can quickly chill your wort to 70F in as little as 10 minutes by connecting the chiller to a tap faucet. Areas with higher groundwater temperatures may require the use of an ice water bath and a pump to circulate the water. The other advantage of using pump is lower overall water usage, which is particularly important if you’re in drought-stricken California.

In short: an immersion chiller is a fancy pipe that uses basic physics to cool your wort quickly, reducing the chance of infection, and shortening your brew day in the process.

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What Do I Need For A DIY Wort Chiller

The parts listed below were used to build a chiller that fit the size of my brew kettle, so don’t worry if you can’t find the same sized pieces. I suggest talking with a hardware store employee to ensure all the fittings connect nicely with each other. With the brass fittings I ended up using, and the pump, which I got from a friend, the total price was around $50 and total build time around 1 hour. You'll need:

  • ⅜” Outer Diameter (OD) 20’ soft copper tubing, adjust length depending on size
  • ⅜” to ½” Compression Adapter
  • Copper wire between 18 and 14 gauge
  • ⅜” Silicone Tubing
  • Tube clamps
  • Empty paint tin of diameter 6-8”, as long as it is at least 1” smaller than brew kettle diameter.
  • Submersible Utility Pump - Optional

Now I Just Wind The Tubing Around The Paint Tin, Right?

That’s the basic idea, however the challenge is twofold. First, copper is soft and can easily pinch if bent too tightly or too roughly. Secondly, it’s important to leave the right amount of tube at both ends to reach up and out of your brew kettle.

My kettle is 10” tall and 8” in diameter (small, for 1 gallon batches) so I used 20 feet of tubing and a 7” paint tin. If you brew more than 3-5 gallons, I'd look to make your DIY wort chiller 50 feet.

  1. Start by winding the tubing around the bottom of the paint tin, leaving at least 3’ sticking out and unwound. We’ll make this the water entrance and use it later.
  2. As you wind the tubing around the paint can, leave ½” of space between each wind, folding very gently. If you want to be extra sure, you can use a spring bender, although I have not personally tried this.
  3. Continue winding around the paint can until your chiller is at the desired height, or when you only have 2 feet of tubing left. This will be the water exit.
  4. Next, sit the coil on your work surface, the water entrance end on the bottom, and gently bend the exit end so it points upwards. Bend half of it outwards so it bends back down at least 90 degrees. See photo above for an example of this.
  5. Gently bend the entrance coil (which should be sitting on your work surface) to vertical so it becomes flush with the coil. You can have it sit on the outside of the coil (easier) or carefully wind it up the inside (harder, but neater).
  6. Measure 2 lengths of copper wire that are each 2.5 times the height of the coil, e.g. for an 8” high coil, cut two 20” lengths of wire.
    DIY wort chiller 2 Fold & Weave the copper wire between each row of copper tubing.
  7. Fold one of the wire lengths in half, and weave this between each coil starting at the bottom, putting a twist in between each coil. Repeat on the other side of the coil. This creates some structure and holds the coils together. Use some short lengths of wire to fasten the entrance and exit ends to the coil. See photo below for an example of this.
  8. At the exit end of the tubing, slide the tube clamp over the end, then slide a length of silicone tubing over it - at least 3 feet. Slide the clamp back over the joint and tighten.
  9. Attach the compression fitting to the entrance end of the tubing and secure tightly.
  10. Attach any other adapters you need depending on faucet size or hose connection you wish to use. When attaching threaded fittings, I recommend using teflon tape to ensure a watertight seal. Once this is complete, you’re DIY wort chiller is complete, and it’s time to test.
DIY Wort Chiller 3 Attach the hose or sink fitting and a length of tubing to each respective end.

Testing Your DIY Wort Chiller

Check for leaks by attaching your water source to the entrance pipe and putting the exit pipe in a sink or bucket. Run the water and check for any drips or leakage at both entrance and exit joints. If all looks secure, you’re ready to test your new chiller on your next batch of homebrew.

To use your new DIY wort chiller, immerse the chiller in the boiling kettle when you have around 10 minutes of boil time remaining to ensure tubing is sterilized by the time it’s time for cooling. Once boiling has finished, connect your water source to the entrance tube, point the exit tube to a drain and let the water flow!

Of course, the specifics of your chiller design and parts will vary depending on your setup but hopefully the above guide should outline the basics. Happy chilling!

If DIY isn't your thing, Homebrew supply offers a wide variety of wort chilling options in both copper and stainless steel. We also carry plate chillers and counterflow chillers as alternatives to immersion chillers.

 

written by Sam Dalton

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