Gregory's Server@rek I'm curious about your process--we regularly have various ferments going but all are open-air in the sense there's no seals between the outside and the medium. However, there's never a case on our end where it's not anaerobic as it's ultimately submerged in liquid from one source or another.
Ultimately, I guess what I'm asking is: are you relying on the jar to maintain an anaerobic environment, and why not maintain the environment with liquid instead?
@kevin The carrots in that jar were dry-salted, it's usually enough to just-cover them. Problem in this particular case may have been more than one thing. I may have overfilled the jar? When i do some liquid spurts out and it sometimes appears like there's less cover (carrots also expand in the jar, get pushed up and out of the liquid sometimes when fermentation starts) and i imagine that this paired with air coming in may have caused it?