Gravity transfer it looks.I’m sure it’s possible. The more sophisticated brewers here will surely chime in.
I always gravity fill through an open lid. Why? Because it’s easy. And I haven’t been convinced of the need to try another way.
But…
If you can forgive the artistic skills at play, I’ve always thought about trying this. I believe the theory is relatively sound but I’ve never yet felt the inspiration to try it. Consider this a tech-free, pseudo-low O2 transfer. I wouldn’t doubt there are easier and/or better ways though.
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I ferment with gas going through serving keg as in illustration A (top)
Gravity transfer I've done but X2 and both were PITA I got half done but ended up pushing the rest with Co2 I could of had a leak or done it wrong though...