I brew big beers, usually 18 to 23 pounds grain and 8 to 10% ABV using dry yeast only. Have been reading about aerating big beer wort to give the yeast enough oxygen but does this apply to dry yeast?
From the Danstar FAQ:
I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?
No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.
If the slurry from dry yeast fermentation is re-pitched from one batch of beer to another, the wort has to be aerated as with any liquid yeast.
Does the above apply to big beers or is it better to aerate? I typically hold drain tube from cooled wort in brew pot well above the wort level in the fermenting bucket. Is further aerating necessary for big beers? If so, how to aerate? An aquarium pump for a 5 gal tank and a small stone cost $10. Devises that use oxygen cylinders are faster and provide more oxygen but they cost $40 and more. If you aerate what do you use. Can a small fuel filter be used to trap impurities from the air?