Unbleached Muslin Kombucha Covers - 4 Pack with Rubber Bands - 10" Square Fits Wide Variety Of Jar Openings - Tight Weave Keeps Flies Out - Let's Your Kombucha Breathe - Hand Wash;

Kombucha fermentation requires air flow, so you can't put a lid on your fermenting vessel and deprive it from oxygen. You don't want to leave the opening uncovered, either, because fruit flies or other bugs can infest and lay eggs on your SCOBY. To avoid this, use a tightly woven but breathable cover on your kombucha vessel to provide the perfect environment for a healthy brew.