I want to take a stab at an open fermentation of sorts, using the wyeast ringwood strain, and can't completely determine the answer to a couple of things. So looking at my proposed procedure:
I'll use a plastic bucket, cover lightly with the lid, without sealing it, such that air can escape. Perhaps crack it a little once krausen is evident. Once the krausen is settled, however, could I seal the lid to prevent oxidation/contamination? Nothing I read suggests this, so would sealing the lid screw with the fermentation conditions enough that the yeast would go dormant or behave unpredictably?
Also, I never bother with a secondary, but everything I read about open fermentation says that a secondary is necessary for conditioning, and suggests getting the beer off the yeast sooner than I normally would. In a closed/sealed fermentation, I just leave the beer in the primary for usually three weeks or so just to make sure byproducts get cleaned up, but would this be a bad idea in an open system, if the primary is sealed after the krausen settles?
The obvious solution might be to either A) screw the open ferment or B) suck it up and use a secondary, I'm just wondering whether there's any particular reason not to seal it off and leave it in the primary.