Homebrew Beer Blog - Latest comments on Dissolved Oxygen: When is it too much?

In response to: Dissolved Oxygen: When is it too much?

Keith Brainard [Visitor] — Fri, 14 Mar 2008 01:41:33 +0000

It's just totally awesome that you're measuring actual DO rather than just guesstimating a time dosage of O2 or even using a flowmeter.

I think that regardless of the other variables, you should be shooting for about 10 ppm DO. I would expect that the oxygen is mostly used right away, so pitching temp wouldn't matter so much, assuming you pitch at a temp that your yeast is happy with. I also think that 10 ppm DO assumes a fully viable and vital yeast pitch with the appropriate cell count for your volume and gravity.

If you're using air and not O2, it's a lot harder to oversaturate your wort with oxygen. Air is only about 21% oxygen, so it makes sense you'd be able to get a lot more DO with pure O2.

Your experiments should be interesting. Especially since it is a little harder to accurately measure yeast vitality and viability unless you have an elaborate microbiology lab.

In response to: Dissolved Oxygen: When is it too much?

Mike Flaminio [Member] — Fri, 14 Mar 2008 01:53:08 +0000

Thanks Keith -- You're right that temp doesn't matter when measuring. Those thoughts were perhaps a little random. What I was getting at, is how big of a difference would oxygenating, using time or some other arbitrary measurement, for an ale pitch be from a lager, say 65 vs 45 degrees. I can brew a mean ale, but my lagers are problematic with ethyl acetate, which should be coming from a fermentation issue. I'm a little optimistic that this supersaturated wort w/ lots of viable yeast could be the cause. Different yeast behave differently, and I am pitching 2x on my lagers, so a few things could be contributing to this. I suspect, however, whatever I figure out for my lagers will benefit my ales.

From all that I've read, I think 10 +/- 2 ppm work just fine for all styles, perhaps a little more for high gravity ales. Should be an interesting road ahead.

In response to: Dissolved Oxygen: When is it too much?

Dave [Visitor] — Fri, 14 Mar 2008 03:58:52 +0000

Thanks for collecting this data, homebrewing needs a lot more hard facts and less old guys throwing out anecdotal evidence as truth.

In response to: Dissolved Oxygen: When is it too much?

Kraig Bridgeford [Visitor] — Thu, 27 Mar 2008 03:30:02 +0000

Hello, I am a brewer & lab tech at a 35 thousand bbl brewery. I like would like to join your diologue, Personally at home i use an air copressor and a seterile air filter with a 2 micron stone at 5lmp. At my work we use tanks of oxygen at 3lpm the entire knock out which gives us 13 ppm of oxygen. One of the biggest things is to pitch viable yeast at high pitch rates about 1lb a barrel. Also we shoot for under.02 ppm of oxygen in the finished beer, I usally get around .01. One point though it is hard to oversaturate your wort because after a point it will just bubble out of solution, another thing is it can cause oxidation of your maltose. My tip is to aerate well, but mostly pitch adequate healthy yeast rates. If you would like to compare readings let me know, we have a DO meter that was 13 grand, its the cadillac of DO meters. Keep it up!

In response to: Dissolved Oxygen: When is it too much?

Mike Flaminio [Member] — Thu, 27 Mar 2008 14:47:18 +0000

Kraig,

Thanks for your input. If you're up to it, try getting as much DO as possible in a 5 gallon bucket, and check it periodically. See how much you can get in there and how long it takes to get down to 8-12 ppm.

In response to: Dissolved Oxygen: When is it too much?

Mark Prior [Visitor] — Sun, 08 Feb 2009 02:43:17 +0000

Thanks for sharing your data.

I'm interested in finding \ deriving a base set of equations that can be used to predict DO levels in wort. I recognize that there are many variables (wort gravity, termperature, desired results, yeast variablity, method of application). These equations could be used much like we currently use IBU equations to project bitterness.

First of all, are you aware of any such equations?

Would it be possible to use your data and specs to derive a set of equations?

Finally, what meter are you using?

Thank you and good luck.

In response to: Dissolved Oxygen: When is it too much?

Mike Flaminio [Member] — Sat, 28 Mar 2009 13:15:25 +0000

Mark,

No.... I think the big problem is utilization. It seems very difficult to know how much O2 is actually getting into solution. This is why I came up with the "Super fast, efficient, and kind of consistent oxygenation" by oxygenating headspace instead of liquid. You might be able to figure something out there, where you can flush a known volume with O2 and then agitate it into solution. I was never great at chemistry so, I'm certainly not your man for that.

The meter is a Milwaukee SM600 I got off of ebay relatively cheap. It's an awesome brewing tool, but to be honest, I rarely check anymore because my method is, in fact, pretty consistent.