6 replies to this topic

[Thirsty]

By no means am I trying to troll up a debate here, I was just surprised at the advice given in the "Ask the professor" column in this month's Zymurgy.The concern was frequent underattenuation. The professor's advice included (his second overall tip) to stop oxygenating. If you haven't gotten your issue yet, it specifically says: "Don't aerate with oxygen. Too much oxygen may be over-stressing your yeast. Use filtered air- it is welcomed by yeast." Now I realize he is possibly just throwing out some ideas here for the guy to try, but I think that sounds somewhat contradictory to most everything else. Uusually you see the opposite, not aerating well enough, and typically pure O2 is the choice for most. Pro breweries do not employ in-line filtered air, they have inline O2. Seems that his suggestion should have been to monitor O2 flow rates if that is his technique, trying first maybe to cut the rate in half and see if there is a difference. Then tinker from there.Perhaps I am reading too much into this and splitting hairs, but the gist of the article he is telling readers that filtered air would be a more desirable delivery of O2 then diffusing pure O2. I just cant agree with that.

[djinkc]

Yeah, I didn't buy into it either. I suppose oversaturation can be a problem but under aerating/oxygenating is probably more common.

[DaBearSox]

I have not read through the whole issue yet, but I think there was an article about Sierra Nevada and it also said that they only use filtered air and not pure oxygen...Maybe Basser will chime in.

[3rd party JKor]

Chemically, that argument doesn't make sense to me. The oxygen in air is no different than pure oxygen, it's just harder to get it dissolved. If the end result, whether you aid air or oxygen, is that you end up with 12ppm of dissolved oxygen, I don't see how it matters how you got there. Maybe the issue is people are overoxygenating with pure o2?

[djinkc]

Chemically, that argument doesn't make sense to me. The oxygen in air is no different than pure oxygen, it's just harder to get it dissolved. If the end result, whether you aid air or oxygen, is that you end up with 12ppm of dissolved oxygen, I don't see how it matters how you got there. Maybe the issue is people are overoxygenating with pure o2?

If I'm remembering this correctly you can only get to 8ppm with air. And that's good enough for me but I don't make huge beers that often. If I did there would probably be an O2 tank around here.

[3rd party JKor]

If I'm remembering this correctly you can only get to 8ppm with air. And that's good enough for me but I don't make huge beers that often. If I did there would probably be an O2 tank around here.

I had heard the same, but I've also heard that 12ppm is optimal and can be achieve with about a minute of pure O2.

[ThroatwobblerMangrove]

I recently had my first beer that I put pure O2 into and it's a great beer. I ran about 2.5-3L of air into 5 gallons.