Using Olive oil instead of Oxygen

[Denny]

When you pitch the yeast - If there is Oxygen available , yeast will use it to respire (use Oxygen to produce ATP) while consuming the sugars in the wort, and not produce Alcohol. Once the available Oxygen is gone, yeast will revert to fermentation to produce ATP while consuming the sugars in the wort.
There is no chance Oxygen will be left over, unless some is in the head space, or introduced when racking.


As for how much Oxygen to add when pitching, many home brewers splash the wort/shake the bucket etc with good results. For higher gravity beers you may want to Oxygenate the wort.

Actually, due to the Crabtree Effect, both take place simultaneously. Crabtree says that in the presences of a >.5% glucose solution, fermentation will begin immediately.

 

[ArcLight]

Actually, due to the Crabtree Effect, both take place simultaneously. Crabtree says that in the presences of a >.5% glucose solution, fermentation will begin immediately.

I had left that out so as not to go into too much detail.
My understanding of the Crabtree effect is it's due to the over saturation of the respiratory pathway and won't produce nearly as much ethanol as if there was no Oxygen present.
But you are right, Ethanol will be produced, even in the presence of Oxygen.

While fermentation is far less efficient than respiration at producing ATP, its a lot faster.


What I mainly wanted to point out is yeast will scavenge O2 fairly quickly so having "an Excess of O2" at the start of fermentation isn't a problem.