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, 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. 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.
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:
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.
Attach the hose or sink fitting and a length of tubing to each respective end.
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.
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