I just bought my friend’s immersion chiller and put it to use for chilling the wort of a porter that’s currentlyfermenting. It’s a nice, fast method compared to the ice-gallon-block method I was using. Below are a few tips and tricks I picked up:
Hook up your chiller first and ensure it’s in working order before brewing. Make sure your connected chiller can reach where the hot wort will to be located at brew time.
- Blast a bunch of water through your chiller just before running your chill water through it to purge the air from the lines. Air in the line can manifest in pockets (bubbles) in which no water is contacting the copper tubing wall, thus reducing your chilling efficiency. (Though I hadn’t thought about this at the time [even though it makes total sense!], I did this by accident. My friend who sold me the chiller told me about this afterward.)
- Gently move the chiller around and use your thermometer to stir the wort as it cools for better efficiency, faster cooling, and a more accurate reading of your wort temperature.
- Calculate your wort chill target temperature (to quickly and cleanly get to a nice finished pitching temp) by following these steps:
- Before brewing, run cold water from your make-up source (sink tap or whatever) until the water stream gets to steady-state temperature. Measure this Make-up Temperature (MT).
- Determine the target Pitching Temp (PT) per the requirements of the yeast strain.
- As your wort is about to finish, estimate the Volume of Wort (WV) in your pot. All you can really do is estimate if you’ve got no volumetric marks in your pot – but try to be as accurate as you can. Remember, your chiller takes up a little volume.
- Find the target temperature of the undiluted (pre-make-up) wort using this formula
WT = (PT* TV – MT*VM) / VW
(derived from formula below)
WT*VW + MT*VM = PT*TV
WT = the final temp you want to chill the undiluted wort to (°F)
PT = Pitching Temp (°F)
MT = Make-up Water Temp (°F)
VW = Volume of wort in kettle at end of boil (gallons)
VM = Volume of make-up water you’ll need to use (gallons)
TV = Total volume of your beer (VW+ VM)
Note: °C can be used, and other volumetric units can be used, but of course you must use consistent units across the whole equation!
Example of chill temp calculation in use:
- My cold faucet tap water measures about 53 °F.
- I have yeast that should pitch at 70-75 °F, so I’ll set MT to 72 °F to give some leeway in either direction (say, if my VW estimate was a little off).
- My final volume of wort in the pot after 60 minutes (accounting for volume taken up by the wort chiller) appears to be about 2.75 gallons.
- I’m making a 5 gallon batch, so make-up water will be 2.25 gallons. Thus:
WT = (72* 5 – 53*2.25) / 2.75 = 87.5 °F
So I want to stop chilling and add make-up water when the wort reaches 87.5 °F.