How long to aerate a starter????

[Pierre le Grand]

I just got an aquarium pump aerator with the stone and HEPA filter. Here is my question: If I were to aerate my starter how long would I leave it in?

Theoretically, I could probably leave it in the entire period so the yeast never needs to go anaerobic. That way they could just focus on reproduction for a higher yeast count. Could I over aerate it?

Anyone else out there dealt with this one?

I'm tired of underpitching, and getting that sweet nasty beer.

[bub]

you can't over aerate with AIR only pure O2
so let her go, just pull it out before fermentation begins
BUB

[Pierre le Grand]

just pull it out before fermentation begins
BUB

What mean you?

My thought is this. Aerate the starter for a couple of days, and stop right before I pitch. Shouldn't that get you the highest cell count?

[BC]

Not a couple of days. Just about 30 to 45 minutes for a starter. It is not that much volume.

[bub]

my bad, I didn't notice the starter part, thought you were talking your beer.
Yeah you can keep air on a starter the whole time.... afterall that is what a stirplate is doing.
BUB

[Pierre le Grand]

What about overoxygenating the starter??? It would be nice if you could just keep providing oxygen until the yeast depleat all the nutrients...you'd have quite the pile of yeast to pitch.

I'm thinking too much. I'll go fix that

[bub]

Well you kinda want to over O2 the starter... as long as you are using air you are ok. The O2 phase of yeast is the growth phase, hense what you are trying to do with a starter in the first place.
BUB

[yeast_slurry_speech]

You're not going to overareate with atmosphere. The only way to absorb that much O2 from air would be to get the starter so cold that it really wouldn't ferment anymore anyway.

The big problem with oxygen in starters is the oxidized off flavors that are produced. If you create the starter a few days in advance and let it ferment out, then decant the liquid before pitching, you won't transfer those off flavors to your beer.

If you're after a very active starter you can decant at the beginning of the brew day and add a little fresh wort to it. Let it go crazy while you mash and boil. Your starter will be nice and active come time to pitch.