Pour the vinegar and beer into your mason jar.

Mix well.

Cover the top of the mason jar with a couple layers of cheese cloth or a coffee filter and secure with the rubber band.

Place the jar in a dark and a decently cool space for roughly 4-6 weeks.

Start tasting at the 4 week mark and let sit as long as needed to get the flavor you’re after. The longer it sits the better. Once the flavor is where you want it, simply place a lid over the top