CHEM Quizz: How many L. O2 in 5 Gal batch?

[Blue-Frog]

Curious how much O2 (either in g or L.) is on average, required to get oh, say 10 ppm O2 into wort. Naturally it will depend on temp., the stone's pore size, losses through escape & probaply more, but what ballpark figure is required to actually get 8 or 10 ppm O2 into a wort?

What is the average loss of O2 that escapes rather than going into solution?

Should one (in general) use twice the amount actually needed or even more?

 

[xico]

As far as I know, we are kind of stuck in this regard as homebrewers. Unless we have a way of quantifying the gas introduced to the system we can't get much in terms of numbers. Accurate devices are very expensive and require a lot of maintenance.

Every brewery I've been around enough to know oxygenation practices introduces gas inline after cooling on the way to the fermenter. This means gas and wort slosh around in the plumbing and surely get a better yield than what we can do at home. This said, there are breweries that don't aerate beyond the what the wort picks up from kettle to fermentor. No brewery following the purity law in Germany uses O2 which leads me to think some strains benefit from the addition more than others and deserves experimentation.

There is such a thing as over-aeration. Yeast will pull up whatever you throw into the wort in 30-40 minutes. What doesn't go into solution will also be int he headspace of the vessel and they will gobble that up too. But over oxygentation can alter attenuation and growth curves and therefore result in flavor changes. I favor under-aeration. I whirlpool all my batches and then shoot the beer with a tank and stone for 15-20 seconds.

 

[jtratcliff]

here ya go:
https://www.morebeer.com/articles/oxygen_in_beer

 

[Blue-Frog]

Thanks for responding guys.
xico, I had not thought about the Germans; are you sure they don't oxygenate? It certainly isn't in the list of 3 now 4 ingredients but I doubt they totally forego it. Somehow I suspect they get it in there. Not really sure though, perhaps someone will post something about it...

jtratcliff, interesting looking article. I haven't had time to read it yet, but it looks like it might help. Thanks.

 

[xico]

I have had the pleasure of learning and researching briefly at a brewing institute in Bavaria. While there, I met brewers from around the country as well and I made a point of asking when appropriate about gases and salts.

Lactic acid can be from acidulated malt (malt-derived) or from a lactic bacteria brink derived from malt originally. CO2 can only be used to cabronate a beer only if it is harvested and scrubbed clean from another fermentation. You can use a bottle to purge a vessel for transfer but that's it.

O2 is only used in yeast propagation systems and ozone sanitizers as far as I know, same as all Belgian breweries I think (verification someone?). A kettle will take 60 minutes or more to empty. During this time, the wort is whirlpooled so that proteins settle in a neat pile in the middle of the kettle. This agitation adds some O2, and the entry into the fermenter will add a bit more. It is certainly going to be strain dependent. Where I disagree in brewing practices from our friends in Germany is their non-usage of salts. Their dunkel weisses would be much better with a heavy chloride addition to enhance the dark fruits and breadyness.

The difference between 4 and 12 ppm is shown to quantify numbers of repitches in Chris White's Yeast book. The extra oxygen allows the yeast to synthesize and metabolize critical resources to carry them through a terminal beer back to a brink. In my humble opinion, making sure you have viable and vital yeast from an oxygen-rich starter and at the right count and you will not notice the difference unless you are repitching dropped out yeast more than 6-9 times. As a homebrewer, it is much easier to save some decanted yeast from the starter instead of the fermenter.

I have never tested O2 additions side by side with whirlpooled wort. If you are the experimenting type pour off a Liter into a growler or canning jar with an airlock and pitch equally to compare. a blind tasting of them finished and flat with several people might be telling. I'd be curious to know the results if you do try it. Next batch I can do the same.