Dissolved O2 and Wort

[klickcue]

I found this article by Neva Parker of White Labs interesting.
http://www.whitelabs.com/beer/NevaParker.pdf

[Bill]

Interesting read there Chris. I'm now able to use pure O2 in my wort but I am not sure how much time to spend aerating. I have an air stone (not sure of the microns right now, would have to check, it's either .5 or .2, I think) and in-line filters, but I'm unsure what level to have the O2 coming out or the amount of time to aerate, depending on the flow rate. My regulator looks like this:



I previously used the typical fish pump setup with 20 to 30 minutes aeration time. Since O2 only makes up about 20% of what we breath, switching to pure 02 should only require a 1 or 2 minutes, at a guess.

[klickcue]

I also have pure O2 available.

I generally hit the 6 gallons with 2 minutes of O2 with a .2 micron SS stone. I believe that I have read/heard that about 1 minute is enough through a stone. I either hit the wort with O2 or shake the carboy to a froth. I do not have a dissolve O2 analyzer so I haven't any idea what the saturation rate is. Also, I would guess, cooler wort would be better for absorption.

What I tuned into on the article was the yeast in later generations since I sometimes reuse yeast from a previous batch.

I believe that Zamil states in his yeast studies that a 35 mL of yeast will double on a stir plate in 1 quart of wort at 1.040 SG with a aluminum foil cover (correct me if I have misstated this!). I am also a believer in a foil cover for my early wort fermentation to keep the back pressure off the CO2 release. The idea is to drive off the CO2 so that alcohol is not produced and the yeast is allowed to fully develop in an O2 rich solution.

Most brewers know that this exists and I use it religiously
http://www.mrmalty.com/calc/calc.html

I like bugs so this is an interesting part of my brewing. It is just more experiments to play with I have more yeast growing in jugs than in carboys

Kinda long winded

[klickcue]

For those interested:
http://www.brew-monkey.com/brewschool/oxygenation.php

To be fair to the 2 micron stone and the aquarium pump, I don't believe that the pump can produce enough pressure to be effective with such a small stone. That is an awful lot of dead headed resistance to over come.

I am of the opinion that getting the wort temperature down into the low 70/60 degree area to allow good O2 absorption with about a minute of pure O2 or a good shake of the carboy for about the same time or a little longer works out fine.

It seems that I remember that long O2 rates have an inverse effect on the final product since the yeast go through a quick growth phase like over pitching too much yeast into the wort.