Ok, but if arguing a point scientifically, one must use the terms properly. correctly oxygenated wort will have no (or very little) o2 in solution once fermentation begins because it is used brr the yeast during reproduction (lag phase).
Ok, but if arguing a point scientifically, one must use the terms properly. correctly oxygenated wort will have no (or very little) o2 in solution once fermentation begins because it is used brr the yeast during reproduction (lag phase).
There could be o2 molecules bonded elsewhere? Who can even measure the proper amount of a blast from a 02 tank? Who even takes into account the amount 02 already present in the starter?
Unless your judging by flavor and have done things multiple ways then it's just a respew of conventional brewing jargon. imho
So lets break away from the cookie-cutter brewing techniques for a moment.
Let's say you pitched a sizeable starter, could it possibly already contain enough o2?
Lets say you needed 200 billion cells and made a 2L starter that gave you 400 billion.
OH-NO overpitch!, your just dying to type it, I can tell...
But what if its a negligible overpitch? What if guaranteed a healthy ferment without 02 addition? I know it's a big what if if Jamil hasn't said so yet on a podcast. But would an overpitch balance out the lack of 02 for growth while still giving more desirable ethanol and ester flavors than a properly sized pitch into properly aerated wort??
What if we also considered some other downsides to using o2 besides being difficult to measure.
Like fire hazards. I gotta imagine having 02 tanks near a propane burner could very end badly. And what if you had a non-brewing related fire. I'd bet an 02 tank would pretty much ensure your entire building structure would burn down fast.
There is also the expense. I am pretty sure I have $300 tied up between tank/ regulator/ sterile filter, and stainless aerating wand. That could buy me a year's worth of brewing ingredients.
And then the general nuisances like an extra step on brew day. Additional risks for bacterial infection. Having to get the tank filled and hydro'd.
I've tried both methods and found no noticeable difference in the finished beer. Both beers had an OG of 1.038 and both were fermented with Y1469 which in each case was cultured up from 2nd generation slants.
The first beer had no extra aeration given to the starter other than when stepping up and the wort was aerated before pitching, this beer fermented down to 1.010 in 7 days. In the second beer the starter was aerated by pouring from one jug to another several times at pitching but no aeration was given to the wort and finished at 1.009 after 7 days. Final beer pH was almost identical at 3.98 and 4.02 and there was no apparent difference in taste from very similar recipes that could be attributed to the methods used. I think that in future unless I'm brewing very strong beers I'll just stick to aerating the starter.
They recommend air, not O2, and suggested that splashing during transfer to the fermenter was more than adequate for 5 gallon fermentations.
What's the rationale?
FOLLOW-UP:
I promised follow-up after the UC Davis Brewing Micro course so here it is:
They recommend aeration in the starter and the wort since you are creating biomass in both places.
They recommend air, not O2, and suggested that splashing during transfer to the fermenter was more than adequate for 5 gallon fermentations.
And here was the real surprise; they recommend just pitching the vial/packet/pouch for 5 gallon batches and to not bother with a starter at all. I suspect this is a microbiologists focus on sanitation/contamination rather than on high quality beer but I have requested more info on this view.
Also, unless you are top cropping, do not bother with acid washes. When bottom cropping there is no real threat of Obeseum (as there is with top cropping) and acid washings real purpose is to fight Obeseum contamination. If you do acid wash, pitch the washed yeast immediately, it is not a storage technique.
FOLLOW-UP:
And here was the real surprise; they recommend just pitching the vial/packet/pouch for 5 gallon batches and to not bother with a starter at all. I suspect this is a microbiologists focus on sanitation/contamination rather than on high quality beer but I have requested more info on this view.
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