Since I usually make small 2.5-gallon batches, I just put my brew kettle into an ice bath in my kitchen sink to chill.

The notes that came with my extract kit say to cool the wort to 70 degrees "as fast as possible to prevent an infection."

But how fast specifically should that be? Using the ice bath method and continually adding ice as the old ice melts still takes about 30 - 40 minutes to get from boiling to the target 70 degrees.

Is that length of time going to be bad for the brew, or is it fast enough? Am I doing something wrong if it takes me that long?

  • Have you had problems with your beer in previous batches?
    – Mr. Boy
    Jan 5, 2022 at 16:14

3 Answers 3


If you can't cool with forced cooling, make sure that your brew kettle is covered adequately.

I started out the same way as you, small brew kettle in the kitchen sink, using ice and water from the faucet. Later on I used a spiral cooler. Now I cover my brew kettle with the lid and a heat proof plastic bag sealed well (when still hot) and let it cool overnight.

Contamination (not infection) is very unlikely if you work clean, and in a clean environment. A clean environment is: not dusty, and no fruit flies in the vicinity. Wash your hands and disinfect the tools that you use and could come in contact with the wort.

  • Not sure what you mean by "contamination (not infection). Infection is contamination with a microbe. Spoilage occurs when that microbe multiplies. This is temperature related. Contamination with non-microbial contaminants, on the other hand, is undesirable (who wants dust or dirt in their beers?) but is unrelated to temperature. Dec 22, 2021 at 10:39
  • @FrankvanWensveen: beerandwinejournal.com/its-not-infected
    – chthon
    Dec 22, 2021 at 13:37
  • that article appears to use the medical definition of infection to make the point that beer is not a human body. We're brewers, not doctors. :-) Dec 23, 2021 at 9:51
  • You can't arbitrarily redefine a word because it suits you. Beer is part of organic chemistry and biology. Infection is always the wrong word. Someone professional in the industry will use the word contamination. If he would use "infection" in an exam, a master thesis or a doctorate he will get remarks. Also: en.wikipedia.org/wiki/Infection, en.wikipedia.org/wiki/Contamination I know that all hobby brewers like to use infection, but it is the wrong word (just like oxidisation, which is grammatically incorrect)
    – chthon
    Dec 23, 2021 at 11:44
  • 1
    Er..I think that's how language works, it changes as we do. Search on this SE. Infection yields 479 results. Contamination yields 119 results. If you're going to fight this pedantic battle- it's going to be uphill.
    – rob
    Dec 23, 2021 at 14:40

There are several reasons why wort should be chilled as quickly as possible. One is to get through the "danger zone" between anti-microbially hot and cold as quickly as possible. The other is to promote "cold break" which is the settling out of proteins and other compounds during chilling. The quicker you chill, the better the cold break and, generally, the clearer the beer.

However, "as quickly as possible" is just that. If you don't have plate chillers and refrigerated glycol below freezing point (which is what commercial breweries use) you use whatever you have. A reflux chiller with refrigerated water is better than an immersion chiller with unrefrigerated tap water, but that in turn is still a lot better than letting the wort cool down naturally overnight. Putting your brewing pot into a tub of water orice is also a lot better than nothing.

The rule of thumb is indeed "the quicker the better" but there is no hard-and-fast rule on how quickly the wort MUST be chilled in order not to ruin your beer. So do the best you can, and only if the results are disappointing (microbial infection, chill haze or other defects related to chilling problems) upgrade to something more complicated.


Don't worry.

I've been brewing for over 10 years and I always just let the hot wort cool on the kitchen counter over night. The key is to close the fermenting bucket (and out an airlock in) so that nothing gets in. As a side effect the hot liquid also kills any bacteria that might have gotten in the bucket before.

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