The widget on top of the jar is from a company called Masontops (not a sponsor). It’s a one-way valve made of silicone that lets fermenting gasses escape without letting oxygen in. I bought myself a set for my birthday. They just arrived this morning, so I immediately made something to try them out, then hop on here and share the love.
It’ll take at least a week before it’s anything of note. Check back then for an update!