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-   -   O2 Results from my new O2 meter! (http://www.homebrewtalk.com/f163/o2-results-my-new-o2-meter-318420/)

wottaguy 04-03-2012 09:03 PM

O2 Results from my new O2 meter!

A while back I picked a new disolved O2 meter that reads in ppm just to check the levels of boiled wort to a 90 second pure oxygenated wort and here's what I have found.
It is said that you need from 9 to 11 ppm units of oxygen to promote a healthy yeast growth and a good fermentation of your wort.
I brewed up a Bohemian Lager last week and decided to use my new meter.
After calibrating (and checking it twice), I pulled off a small sample of wort which was boiled for 90 minutes, cooled to 60 degF then checked the O2 level with the new meter. I got an O2 level reading of 1.5ppm. Pretty low!
After stabilizing the temp of the wort and just before pitching, I oxygenated the wort with pure O2 for a timed 90 seconds, then pulled a small sample to be checked with the meter. I got a reading of 17.5 ppm right after aerating. I then waited another hour before pitching and checked it again and got 14.5 ppm!
I pitched the yeast at that time and the lager has been fermenting ever since with a lag time of approx 12 hours.
I do need to say that the yeast (Danish Lager) was grown from 2 wyeast packs in a 2000ml flask and bumped up 3 times then decanted and pitched.
Just thought I'd pass this result along in case somebody is wondering about O2 levels. I now aerate all worts ales or lagers for 30 to 45 seconds.
Hope this helps someone out there......!

sdugre 04-03-2012 09:21 PM

Interesting. I'd be curious to see the measured O2 level after a few minutes of shaking the carboy.

wottaguy 04-03-2012 09:31 PM


Originally Posted by sdugre (Post 3959571)
Interesting. I'd be curious to see the measured O2 level after a few minutes of shaking the carboy.

I can do that...I'm actually brewing right now and am getting ready to start the chill. I'll post my results as soon as I can. I'll measure the levels before and after the shake up! How long do you shake your carboy for?

Good question.

sdugre 04-03-2012 10:35 PM

I actually use pure O2 now, but always wondered how effective shaking was when I used to do it. I probably shook it for about a minute and a half or so.

wottaguy 04-03-2012 10:37 PM

I usually use O2 as well, but I always wondered if it is really necessary. I'll have my results within the hour along with the process I used.

Bobby_M 04-03-2012 10:38 PM

If I understand correctly, the 17.5 ppm was on pure oxygen. It would be better to call that oxygenation because aeration may imply air only.

wottaguy 04-03-2012 10:48 PM

ok...here's my results and what I did:

I took a sample after chilled to 50 degF and I then ran the wort into the fermenter.
I tested the sample and got a reading of 2.3 ppm.
After all the wort was in the fermenter, I capped it and shook it for 30 seconds, then burped the cap, and repeated for 6 times. Wort temp was 50 degF.
After doing this, I removed the same volume that I tested earlier and then measured the ppm. I recorded a reading of 4.6ppm of O2. Not too good for all that shaking.
Bottom line? I'm going back to injecting pure O2 for 45 seconds and save myself some work. All that shaking for practically nothing.
Hope this helps!

wottaguy 04-03-2012 10:49 PM

yes...pure O2 in orig post...sorry (corrected)

Veedo 04-03-2012 11:41 PM

About how much of a flow do you inect with the pure o2? Vigorous, or just so its bubbling on the surface?

SwampassJ 04-03-2012 11:51 PM

I wonder how much you gain from things like pouring through a funnel and how much from a drill stirrer. I've put off getting the Oxygen kit for almost 2 years now. Might be my next big step up in quality.

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