Just read through the full thread. I recently found Hull's paper after the head brewer at Smuttynose recommended OO as a way for a homebrewer to aide the fact that it is tough to get more than 2-3 ppm of Oxygen with splashing/aeration. (and don't want to add to their eqiupment surplus with o2 tanks, aquarium aeration pumps, etc)
I'm not sure everyone posting read or really understood Hull's paper. The tiny amount of OO was added to yeast POST FERMENTATION, while in storage, as a prep for the NEXT batch. I don't want to read into the full details, so biology PHDs, feel free to correct me. But I believe it amounts to the yeast using O2 to process something or other, which ultimately strengthens the yeast. Rebuilding cell walls and making them strong for propagation (yeast sex/duplication). Aeration is a great way to do this, but long term has an impact on storage. Something commercial breweries care about. OO was used during yeast storage, 5 hours before use in this experiment, to allow the yeast to re-strengthen themselves. (Like Pop-eye eating his spinach to prepare for a fight, not after Bluto has already beaten him to a pulp)
The experiment showed that, comparing a beer aerateted to 9-10 ppm of oxygen vs OO, there was not a significant difference. There was a longer lag time and more esters created using OO. This leads you to believe the OO is not quite as good as aeration, but it also replaces negative long term beer storage impacts. And the ester/lag difference can be OK, even mitigated with more OO. It is too bad the experiments did not continue until the threshhold of "how much is too much" was found, to find the optimal amount. But - optimal amount would depend on the yeast type as the paper stated. Something that would really require lots of experimentation across yeast strains
(Side note - there are some comments that New Belgium stopped this practice due to their perceived impacts to longer term storage. Does anyone know this as fact? This would be a cool thing to get a comment on from NB. I assumed they stopped practice of this right after the experiment because using O2 is the old reliable method. Actually, probably only using OO for these tests and then back to their normal procdess. Did they measure storage past the 3-4 weeks that was discussed in the paper results, which showed OO held up better? Extrapolating those results would give the edge to OO. And remember - they did actually sell the OO version to paying customers after passign all in house tests)
What would be more interesting to a Homebrewer that doesn't have an aeration stone - what are the scientific results of this using the splash/shake method (which is somewhat understood to give 2-3ppm) versus using a drop of OO - at the right time.
Sounds like most people have been adding that drop to the fermentor. At that point, the yeast have been diluted throughout the full 5G of wort (not sure what impact that would have, putting in the drop of OO) and the yeast would have started to propegate right away anyway - eating the newly found sugars! They would be doing this with their puny, unhealthy cell walls. If this is how people were experimenting, they were not following the process and missing the point of the use of OO.
I've had trouble getting those last few points of attenuation. I was about to give into an aeration stone because I know I'm far short on needed oxygen. However, just started with the OO method.
For the last batch, made the starter as normal, after 36 ish hours it was put in the fridge to drop the yeast so I can pour off the wort. 5 hours before I knew I would pitch, with the yeast at room temp again, 1 tiny drop of OO was added to my starter flask. This was all pitched to the wort.
I wish I had read this thread first. My 10G batch was already split to 2 fermentors, but both used the same starter yeast. Next time I'll compare.
This would be a cool experiment for BYO to do. Get a bunch of people to send in batches. 1 using the splash/shake method. 1 using OO. Let them send these off to labs for actual ester/compound/whatever testing - and taste testing. Has there not been more testing on this? I'm just starting my Interwebs search for more information now. I'm surprised this thread was started 4-5 years ago and I don't see a lot of other good information on it. Maybe that does mean its truly a failed method. But haven't seen any proof for that.
Thats my 50 cents. Reading Hull's thesis made sense. Seems like people just adding OO to the fermentor though is not nearly following a process that would create any benefit to using the OO. Missing the point. I do wish the initial experiments were expanded upon, but if that was all that was required for the PHD paper I would have stopped to. Writing papers is annoying. Can't believe I rambled on this long in this post.