I use an aquarium pump and stone to aerate wort, with an inline “wheel” air filter. After doing this for years, I’ve managed to get two of those filters plugged in the last two months of brewing. That’s very annoying and could get expensive if it keeps up (nearly 5$ per).
In How To Brew, Palmer has a diagram for a homemade air filter, using “wet cotton” in a tube. Color me doubtful… but then, people use all sorts of methods that pull in contaminated air into the wort, all apparently without a problem: mix-stir, shaking, dropping and pouring, etc. I’ve even read on the Aussie brewing forum about guys using the pump with no filter at all, without a problem. (But hey, that’s the aussies for ya )
So what the heck. At least with this method, you’re trying to filter some of the bacteria out. I was thinking if the cotton has to be wet, why not use star san too.
Any reports on this method?
And yeah, I know I could go the pure oxygen route, but don’t want any more specialized gear than I already have. My current setup works well, even for big beers; I just hit those a second time 12 - 18 hours later if I think the yeast need it.