When I started brewing I used a plate chiller to chill my wort. I didn't like the process, and now I add cold water after the whirlpool and to get the wort down the last 10°C I put into my fermentation chamber with temp control.

I am aware of the infection risk, and am still wondering if this style of cooling will influence the taste of my beer. I don't recognize any off flavors.

Edit: I design the recipe with the addition of the water that I add after the whirlpool. BrewSmith calculates the changes in IBU, final gravity and so on.

  • How long does it take to reach your final temperature with your new cooling process?
    – Philippe
    Mar 21, 2018 at 16:38
  • It takes 6-7 hours Mar 22, 2018 at 6:24

3 Answers 3


Usually the biggest concerns of a slow chill are....

DMS (cooked corn flavor) is created from SMM when wort is hot. DMS will form until below 140°F (60°C). SMM is boiled off during boil, it's why we do an open lid boil. SMM has a half life of 37 minutes. 90minute boils usually reduce SMM levels below the perception threshold.

Unwanted bittering late addition hops (less than 45min) continue to isomerize until wort drops below 175°F (79°C)

Infection bacteria love warm temps. Below 160°F (71°C) (pasteurization temp) the wort is at risk of infection.

As far as adding cold water to chill, this could be very effective at dropping the wort below those critical temps very fast. But I would make sure the water is sanitary or sterile (pre boiled, chilled, sealed)

As far as the last 10°F(~5°C) allowed to slow chill. It's a common practice with few side effects other than risk of bacteria taking hold before yeast gets going. It may in some cases delay your pitch and add to the overall brew to glass time.

Update: forgot this initially.

Chill Haze when wort cools slowly this allows certain proteins to remain suspended resulting in chill haze. The thermal shock of a rapid chill of the wort causes them to drop out. Usually have to drop below 80°F (27°C) within 15 minutes for sufficient thermal shock. Chill haze is identified in finished beer by being hazy when cold but then gets clear when it warms up.

  • Pasteurization happens below 160°F, it just takes a lot longer. This is why sous vide long cooking times work. Here is the chart sousvide.wikia.com/wiki/… Mar 21, 2018 at 18:53
  • @farmersteve true most pathogenic bacteria only need temps above 140°, and many can't survive lower temps if held for a long time. And then there's botchulism bacteria which can survive up to 250°F. Mar 21, 2018 at 19:07
  • @EvilZymurgist:It is not the bacteria, it is the spores of the bacteria which can survive those circumstances (*botulism)
    – chthon
    Mar 22, 2018 at 7:44
  • @chthon which is just a dormant state of the bacteria. Much like dry yeast. ;-) Mar 22, 2018 at 12:18
  • Survive what circumstances? If you heat your wort over 180f for 5 minutes you've killed the spores so cooling it down with little exposure to the elements is not going to create an environment where the spores can get into your wort. The incidence of botulism is quite rare and is mostly found in home canning so I would say the chance of getting botulism from wort that cooled over a long period of time is near zero. en.wikipedia.org/wiki/Botulism Mar 22, 2018 at 16:33

I can think of a few possible things that might differ (assuming your recipe takes the cold water addition into account):

  • You've already mentioned the sterilising effect of boiling.

  • Boil volume can have an effect on hop isomerisation - the lower the volume, the lower the IBU.

  • pH has an effect on hop isomerisation.

  • A change in cooling rate will also affect hop isomerisation, though this is a commonly consideed variable anyway.

(See https://www.sciencedirect.com/science/article/pii/S0308814610006643 for some info on these effects).

  • Boiling water also boils off chloramine, which can give off flavours in the final beer (if using mains water which has been treated with it).

  • Caramelisation and maillard reactions may be affected by concentration.

  • That aspect I forgot to mention: I design the recipe with the addition of the water. Mar 21, 2018 at 15:27
  • Updated to add more specific details and remove comment on recipe changes - you might want to edit original question to avoid someone else offering the same advice!
    – match
    Mar 21, 2018 at 16:04
  • Thanks, I wasn't sure if I was allowed to edit after the first comment. And I edited my question. Mar 21, 2018 at 16:23

Try No Chill brewing where you don't worry about chilling the wort. https://beerandbrewing.com/no-chill-brewing/

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.