I'm going to use my o2 wand on the starter for my next batch because according to mrmalty it cuts down on the size of the starter needed and I am not made of DME. When I oxygenate I turn the regulator on full blast. How many seconds should I do for a 5 quart starter? I know it's not exact science, but I'd rather under oxygenate than over, so give me a rough estimate.
How much pure o2 in my starter?
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Brewer3401
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You could add O2 until the bubbles almost come out the top of your starter vessle, then let them dissolve, then repeat 1-2 times.
Also, the colder your starter, the more O2 will go into solution.
I think if you do 2-3 times, you'll be close to O2 saturation.
I used to do this, but got lazy and I just shake my Erlenmeyer flask to get oxygen in.
My attenuation is extremely good doing the shake method, but I'm sure I may get a little quicker start if I used a ton of O2 - that's based on some technical papers I've read.
Also, the colder your starter, the more O2 will go into solution.
I think if you do 2-3 times, you'll be close to O2 saturation.
I used to do this, but got lazy and I just shake my Erlenmeyer flask to get oxygen in.
My attenuation is extremely good doing the shake method, but I'm sure I may get a little quicker start if I used a ton of O2 - that's based on some technical papers I've read.
A bit hard to quantify "regulator on full blast". Is that an actual regulator, or a needle valve? And are you using an air stone, or an open wand?
With a good (.5 micron stainless steel) air stone, if your starter is a quart of around 40 point wort and you pushed in a liter or so of O2, if you assume a 50% absorption rate you'd be in the 20ppm range which is about as high as you want to go (40ppm gets into the toxic-to-yeast range).
With an open wand the bubbles are comparatively humungous and absorption is a lot lower. I wouldn't even begin to guess how many liters of O2 at "full blast" you'd have to push to hit 20ppm with that setup.
For reference, the best O2 concentration you can achieve using atmospheric air is 8 ppm...
Cheers!
Er yeah, should have qualified...It's a .5 micron. I guess it's just a needle valve on the tank. For reference I usually do 60-90 seconds for any high gravity beer I'm going about to pitch into. I just want to try it on the starter because that damn Mr. Malty thinks DME grows on trees.
