Carboy Rubber Stopper


This #6.5 Carboy Rubber Stopper fits our 1 gallon carboy as well as the lid for Catalyst Fermentation System. Also referred to as a "bung" in the homebrewing community, this Carboy Rubber Stopper provides a seal on your fermenter during fermentation, while supporting the airlock or blow-off tubing. 

This exact stopper comes standard in our 1 gallon beer, wine, hard cider, and mead kits, our Extra Fermenter Kit , and The Catalyst. This Carboy Rubber Stopper is a perfect replacement if you need another Catalyst stopper, have misplaced this item, or are just ready to retire an old one.

NOTE: Other brand fermenters may use a different size or style stoppers - sizes cane range from a #2 to #10.


Stopper hole is 3/8" in diameter
Compatible with our 3-piece airlock, 1 gallon carboytransfer tubing & Catalyst Fermenter.

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