It's time for some summer brewing and that means the warm tap water running through my wort chiller will have trouble cooling my wort down below the upper 70s. Even for the Belgian style beer I'm brewing this would be too high of a pitching temperature per the recommendations.1

Based on related posts here, I am comfortable throwing my brew pale in my kegerator for a number of hours to cool prior to pitching because of the following:

  1. I am extremely meticulous when it comes to sanitizing my equipment
  2. My brew pail will have little headspace

My question is -- does it matter whether you aerate/oxygenate the wort after initial cooling or are their reasons to wait until you pitch the yeast (say 4 hours later or 24 hours later)?


2 Answers 2


I would oxygenate (pure O2) right before or after the pitch.

Just because the process has the chance to introduce bacteria or wild yeast and it's best if the yeast is there to become dominate before anything else.

Aeration has much less risk, if just splashing or shaking the wort. I don't think this would matter much when it's done.


I concur with Evil Zymurgist and would add the following.

The yeast will need to initially eat up all that oxygen to multiply before getting to work on transforming sugars into alcohol. If you aerate and then wait before pitching your yeast it will be a bit of a fruitless exercise as all of the incorporated air will be lost once you open the fermenter lid to pitch the yeast. This could also lead to the outside possibility of oxidation.

p.s 100% O2 isn't neccessary but is usually best practice.

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