Wild yeast ferments (quick note)

[blasterooni]

Again, i was listening to a podcast on ciderchat.com, and they were discussing wild ferments. The guest said that he tastes his ciders every 12 hours during primary, and when he tastes one he likes at the specific point in the process, he either adds oxygen, shakes the barrel, or splashes the juice to add oxygen. His notion is that this will give a boost to the dominating yeast thus furthering the production of the quality in the cider he tasted at that time. He said further that there is no risk of messing it up since the cider is still early in the primary fermentation phase.

Anyone else heard of doing this? Seems intuitive...

 

[bernardsmith]

Presumably by adding oxygen the fellow's intention is to help the yeast he has detected and which he likes reproduce and so remain the dominant fermenting organism in the mix. If that works and does not then also enable less dominant strains from reproducing perhaps faster than his preferred strain then more strength to the fellow. But I wonder if his inoculation of O2 is in fact producing the results he intends to produce (the better tasting cider) or whether the final result would occur no matter whether he added air or O2 to the mix or not (and it should be quite simple to test this - you simply quickly divide the batch in two when you taste the flavor you are looking for and aerate one but not the second and you then randomly assign two of one sample and one of the second to a group of people and ask them to identify which sample is different and which they prefer... If they can identify the different sample with statistical significance then he may be on to something and if they tend to prefer the aerated sample more than the other one he clearly is doing something right...

 

[RPh_Guy]

I don't think you can test this hypothesis by splitting the batch because the microbes in each batch won't be identical.

Aeration early in the fermentation does alter the flavor, but it's probably not doing what that guy suggests. Degassing and aeration is known to help reduce yeast stress, resulting in lower production of off-flavors, but also lower ester production.

Microbial progression follows a consistent pattern:
Oxidative yeast phase
Fermentation phase
Maturation phase with MLF +/- Brettanomyces +/- aerobic fermentation

You can't choose what microbes dominate by aerating. If anything, aeration will shorten the oxidative yeast phase, resulting in less of the flavor that's present at the time you aerate.

Just my thoughts.