Question for those who oxygenate their wash...

[Ned]

Steve, it seems that you have as much info to back up the opposite point on this as I do. So perhaps the answer is in the middle. From my experience over aeration results in a heavy yeast load and subsequent downstream effects. As an unscientific experiment, we aerated our last batch for twice as long as normal, our yeast load was 2-3 times what we typically see and our yield off the still was reduced by about 10%. So my recommendation to anyone just starting with aeration/oxygenation is to experiment with different flow rates, and times and figure out what gives you the best results. We've optimized for our process and house yeast and won't be altering our process.

On flavor, don't know where I got the DMS but you're absolutely right that it's unrelated to oxygenation.

[Denver Distiller]

As an unscientific experiment, we aerated our last batch for twice as long as normal, our yeast load was 2-3 times what we typically see and our yield off the still was reduced by about 10%.

Therefore, if you want to oxygenate your mash and wind up with less yeast at the start of fermentation, you simply cut your pitching rate (the amount of healthy yeast cells you add), and Bob's your mother's brother.

The Scots, for the most part, don't oxygenate. So you'll find that their pitching rates are twice that of, say, traditional German brewers who oxygenate or even use flotation tanks before they pitch. All things being equal, if you oxygenate the mash before (not during) pitching, you'll find that your yeast will create daughter cells that are roughly twice the original volume. So you'll wind up with three times as much yeast as you started. Things like yeast strain, mash/wort temperature, etc. will obviously have an effect on this number.

[Les Trois Clocher]

Great information here... In my experience you want to pitch high and aerate well to insure a consistent product formation (keep those yeast workers happy and they won't strike via sluggish fermentation and strange off-flavor formation)

I would just like to add a bizarre alternative I've seen to this conversation. One of the breweries I did a brief stay at (internship) used Hydrogen peroxide to get the oxygen into his beer... He claimed it was a great solution since it would also do some sterilization at the same time. His full time job was at a yeast plant so I trust he knows his stuff when it comes to making yeast happy and also the beer tasted great. I wish I remembered the dosage but well I don't and I suck at chemistry but you could draw it out to figure out the appropriate dosage needed to get that needed O2 so your yeastes can bud like crazy, live happy lives, and produce great beer... it also cost less to get a bottle of concentrated hydrogen peroxide and a graduated cylinder then a compressor and air filtering system so it might be worth looking into.