Foam stoppers for glass primary

[giraffe]

Ive done a search, but there wasnt super useful info. Has anyone used the foam stopper one uses for starters in a flask for primary fermentation in a glass carboy, to mimic open fermentation? Im interesting in experimenting with open fermentation with some english and hefe yeasts, but currently my entire setup is glass carboys. And I have an irrational dislike of plastic equipment.

My question is has anyone tried this? And how did it compare to fermentation in a cracked plastic bucket? Were there any sanitation issues? (I usually try to keep my yeast going for 6 or 7 generations before buying a new vial) Is there other methods people have found that work well?

 

[Hermit]

I have used a coffee filter with a band to keep it snug. This is mostly to let air in. Chris White suggests allowing air in until the krausen falls. I use this for my starters also. So far I haven't had insects/fruit flies in my fermentation fridge. I soak the filter in Starsan and wring it out. If gnats were an issue I'd probably put a loose foil cover on over that.

My reasoning would be flies could deposit something onto the filter and if you get krausen/blowoff, then it would touch the filter. You could also put the coffee filter over the end of a blowoff tube and not airlock it.

I have no personal experience with the foam stopper but I don't see why it would be any different.