I extract brew, and the kits I buy from NB tell me to add cold water to the wort to get a total of 5 gallons, and then aerate before adding the yeast.

However, if I do this I will always have more than 5 gallons of total solvent after pouring the yeast in, unless I try to add an amount of water less to the carboy equal to the volume of the yeast.

It would be easier for me to put the yeast in and then top off with cold water until 5 gallons, and then aerate (I use an aeration stone).

Is this OK?

1 Answer 1


It does not need to be 5.00000 gallons, don't worry about the small differences.

You can aerate after pitching the yeast, so long as it's immediately after; the yeast need oxygen during the lag phase, but once alcohol starts being produced, you don't want to introduce oxygen at that point.

  • You should elaborate on what the 'Lag' phase is, anaerobic and aerobic respiration of yeast and I'll give you a +1. Jan 13, 2014 at 13:35
  • Also, you can still oxygenate the wort even up until high krausen, as is common practice for big beers to ensure proper attenuation, without risk of off flavors (24-48 hours after pitching).
    – Scott
    Jan 13, 2014 at 15:34
  • "Lag phase" is really a mienomer. According the the Crabtree Effect, the yeast will start fermenting immediately in the presence of a > .5% glucose solution.
    – Denny Conn
    Jan 13, 2014 at 16:46
  • Well, whether it is called a "lag phase" or not, the point is that you should aerate your wort as best as you can at the time you pitch your yeast because the yeast will spend some time acclimating to the environment, and taking up minerals and amino acids (nitrogen) from the wort. At this time, they can really use oxygen. Many will tell you that you need an oxygenation system. Some research shows that very vigorously rocking your fermenter for five minutes comes close to getting you maximum O2 saturation. For very high-gravity beers, there are different considerations you should address. Jan 13, 2014 at 22:20

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