Originally Posted by Bonysplicer
My understanding is that "oxidation flavors" are caused by excess dissolved o2. From this it would seem prudent to drive off excess dissolved oxygen as quickly as possible, prehaps through agitation in an oxygen defficient environment.
Your statement shows a lack of understanding of the brewing process.
Oxidation flavors are indeed caused by excess dissolved oxygen. However, the prime source for oxidation off-flavors hasn't anything to do with fermentation. It has to do with the mash.
There is a phenomenon called hot side aeration
which sets up the precursors for in-package staling and development of off-flavors that evoke wet cardboard or paper. Hot side aeration (HSA) is caused when sweet wort pics up too much oxygen, usually through excessive agitation.
Before you go all wobbly about HSA affecting your beer, though, take my advice and stop worrying about it. HSA is of concern to large beer factories, where they're pumping wort at hundreds of gallons per minute. In order to induce HSA-derived flavor precursors in your wort, you'd have to pump it through a garden hose at a high rate of speed and shoot it into your kettle.
That said, you can pick up off-flavors from air post-ferment, but it's not from the introduction of oxygen. It's through the introduction of non-S. cerevisae
microorganisms - in other words, contamination. The same flavors associated with HSA can also come from contamination.
I mean to say, how many production breweries still use open fermentation? If ever there was a situation where green-beer oxidation would be virtually guaranteed, it's then. It doesn't happen, because it happens on the other end of the brewhouse. Contamination is also unlikely, provided an open ferment is conducted properly, because infecting microorganisms cannot withstand the environment of high krauesen.
Agitation can be beneficial, however. Yeast strains which are excessively flocculent - Ringwood springs to mind - often need to be roused periodically during the ferment, in order to maintain contact with the wort. Whether it's twice-daily stirring with a sanitized implement or constant agitation with a sanitized submersible pump - I've done both - extremely flocculent strains sometimes need the physical assist. I have to note I've never experienced staling precursors developing with those methods.
It is good to keep beer away from air
after bitter-wort aeration and the onset of the ferment. But it's for different reasons than the development of flavor precursors of oxidation. The moral of the story is "stop worrying about it".
Oh, and about de-gassing: Vintners de-gas their product because it's intended to be still; I for one don't like fizzy Sauvignon, and I'm sure you don't either. Brewers intend their product to be quick (carbonated); a good conditioning regime will take into consideration the amount of dissolved CO2 in the green beer before conditioning and add a proportionate amount of priming solution to reach a targeted volume. Thus de-gassing is a waste of time.
Plus it adds to global warming.