You don't have to answer this question. In my case & I am sure, for many others, oxygen has caused a lot of misery. I had been brewing decent beer and in an effort to make them better, I spent a lot of time listening to beer podcasts / reading books. Most experts advise that one should oxygenate beer as the yeast needs it. Further, there is much belief that one can't over oxygenate as there is a saturation point for dissolved oxygen and that, during fermentation, the yeast consume all of it or it naturally gets removed.
I am sure there is a time and place for oxygen after one carefully experiments with oxygen dosage / results / type of beer etc. But for the average home brewer, I think it is totally unnecessary and in fact down right the biggest culprit in creating higher alcohols and very very fruity esters due to excessive growth. I know this because I have done at least 15 batches of all grain with oxygen and all the time, I kept wondering what is wrong with them. I never had the higher alcohol / excessive fruity esters problem before.
Finally, I backed off on the oxygen and went back to splashing the wort and the results are wonderful. Clean fermentation (unlike funky smelling beers of oxygenated wort), good flavors overall and really enjoyable beer.
So, the lesson in this is - don't alter your process if you are making good beer. Don't over learn. If you want to tweak something, do so in a very very controlled manner!
I AM BACK. BACK TO BREWING NICE BEERS! And, I can't wait to try out the Belgian Pale Ale that is now sitting in my fridge at 1 - 2 C. In a couple of weeks, when all the tannins / phenols have settled out, the beer should taste really special.