Do I really need to aerate/oxygenate my wort before pitching yeast when brewing? If so, what’s the best way to do it?
The short answer is “Yes, you need to aerate/oxygenate your wort.”
While homebrewers consider any oxygen in their finished beer a bad thing, oxygen is critical for proper reproduction of yeast cells during the “lag phase,” when they are just waking up. During this phase, the yeast cells are rapidly reproducing and need oxygen to grow. Unfortunately, the process of boiling your wort forces almost all the dissolved oxygen from it, leaving it oxygen-depleted.
So you need to add some oxygen back into the wort after boiling, but before pitching your yeast, to get a strong fermentation. By far the best way to do this is by using pure oxygen. In fact, one of my new favorite toys is an “oxygen wand,” which is a stainless-steel tube with a stainless aerator at one end. You attach the wand to a tube and a regulator that connects either to an oxygen tank or a disposable oxygen canister. For about $60, an oxygen wand can aerate your entire batch to the ideal 8−10 ppm oxygen content in about 60−90 seconds. I use it after transferring wort to the fermentor, just before I pitch my yeast. It works well with cider, mead, and wine, too.