Total submersion vs punch downs

[FlamingoEmporium]

Not sure, but I think I read somewhere of a device a bit like a coffee percolator with the base submerged in the must. A tube poked above the cap and the action of the ferment bubbled the must out of the top above the cap.
I don't know,at my age I sometimes get memories and dreams confused.

Anybody who isn’t an old fart is saying “what’s a coffee percolator“

 

[BigDaveK]

I’m sure the same applies to the yeast being able to get at the whole cap of must. The more stirring, the more area that gets eaten up.

I can see that.
Water and bubbles follow the path of least resistance. In a short time I imagine small pockets of micro-environments forming, each a little different from it's neighbor.
Lately I've been holding down the cap to maximize flavor and color extraction (at least that's the plan) and I still mix at least half a dozen times a day.

 

[balatonwine]

gas? off flavor? mercaptans? ? ? > > CO2

You have me wondering if part of the benefit to mixing the cap vs a hold down plate is nitrogen extraction from the skins which makes yeast nutrition traditionally good on reds versus fair on whites.

Humm?

I think there are some good basis there for some controlled experiments and a few journal articles....