Okay, I am violating several rules, here. First, this is an old and moldy thread. Second, I'm a distiller, not a brewer. And third, I have no experience in any of this.
That being said, what theeeeeee crap are you guys talking about? I joined just now to simply post about this issue because what is being discussed is just out in the ozone. Anyone ever read the ENTIRE masters thesis by Hull? He wasn't adding OO to the entire wort; he said-
The purpose of this research was to compare the effects of adding olive oil to storage yeast vs. traditional wort aeration. The theory is that the oleic acid in the olive oil will provide the UFAs necessary for yeast growth and proper fermentation, eliminating the need for wort aeration.
That means pre-treating the yeast slurry with oleic acid, replacing the typical process of aerating the entire wort, and thereby improving the resistance to oxidative staling.
This entire thing about micrograms of OO is just pathetic. If anyone ever bothered to read and understand his paper, and I quote-
Due to the variation in yeast slurry thickness the amount of olive oil used was based on the total number of cells instead of mg / L of yeast. In the 360 hl batch the olive oil was added to the yeast at a rate of 1 mg / 67 billion cells pitched (15 mg olive oil / L of yeast assuming a count of 1 billion cells / ml). In the 720 hl trial the concentration was increased to 1 mg / 50 billion cells and in the 2100 hl trials the concentration was increased again to 1 mg / 25 billion cells. Aside from the changes previously mentioned with aeration, olive oil addition and fermentation size, all other aspects of production were carried out identically for both the tests and the controls.
What part of this thesis scales down to micro milliliters per 5 gallon batches? His final (successful, btw) ratio was 1 mg per 25 billion cells of pitched yeast. A five gram packet of dried yeast has 90 billion active yeast cells. If you didn't even grow a starter, that is still 3.6 milligrams of olive oil (or 72 normal drops) per liter STARTER. This whole micro-pipette, micro-milliliter discussion is off the charts. And the kicker is that Hull was scaling UP his experiment from many papers that dealt with <1 liter experiments with oleic acid and ergosterol supplementation.
No wonder that experiments with microliters of OO are anecdotal, that is just silly. Try a milliliter or two with a liter starter (not to mention a 20 liter wort) and you might get close to actually testing Hull's hypothesis. And, btw, his results were that a fully qualified panel of expert tasters found his OO batches the same, or slightly better, than the control. Screw you who say that there isn't any scientific evidence. Impanel your own expert tasters to disagree.
As for the claim that if it worked, they would still be using it, you have to read the ENTIRE paper. The drawback wasn't that it didn't work, or that it negatively affected flavor, but that it took slightly longer to attenuate. In the end, economy of production ruled that it wasn't worth the extra fermentation time, not that it didn't accomplish what it set out to do, and that was to stabilize flavor by replacing initial oxidation of the wort.