Airlock - 3 Piece

QRP excellent quality 3-piece Airlocks supersede S-Curve Bubble Style Airlocks because they are sturdier and easier to keep clean. The 3-piece airlock should be filled only 1/2 full with filtered water and maintained at that level. We shouldn't fill our jar more than 80% with food while fermenting. If we fill our jar above the curve in the jar, the food may expand while fermenting and cause the airlock to overflow.