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- Mar 4, 2009
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All,
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......!
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......!