German Brewing

Almost half way. Its controlled by a brewpi. It uses a small hair dryer on low for heat. Accurate to .1F.

Crashing yeast is dangerous when it's in mid-fermentation. It needs to have finished, then crashing is ok, otherwise one ends up with not-so-nice tasting excretions in the beer.

My old method was stir plates or simply let it stand and settle out. This improved method re-circulates the yeast continuously, thus acting a bit like a stir plate but hopefully with less shear.

It never receives a continuous flow of oxygen (especially pure O2 - It's dead easy to overshoot), but measured, occasional bursts.

Without measurement it all becomes wild guesswork.

Even with drauflassen, the yeast will need oxygen in each subsequent wort addition. They more a yeast cell buds and the older it gets, the more critical it is to get it back to healthy using oxygen.

Drauflassen isn't such a great technique either, as far as quality is concened. Narziss mentions no more than 3 batches as max. Modern methods don't aerate the last batch any more.

As a matter of fact oxygen control during Drauflassen can be a bit of a Pandora's box. You certainly need to measure well and often when doing this.

I'd keep it simple and aim for a straightforward brew which no premature optimisations or fancy techniques.

Solid foundation is everything.