#5 Drilled Rubber Stopper (Bung) for Fermentation

#5 Drilled Rubber Stopper for Fermentation

This #5 drilled rubber stopper is a fermentation bung for compatible jugs, bottles, and small fermenters that need a stopper with a center hole for a standard airlock. It is used in beer, wine, cider, mead, and other small-batch fermentation setups when the vessel opening matches a #5 stopper.

A good stopper fit matters. The bung should sit securely in the vessel mouth without falling in, rocking loose, or needing to be forced. If a stopper is old, stained, cracked, hardened, or no longer seals well, replace it before filling the fermenter.

Best Uses

• Fermentation closure: fits compatible vessels that use a #5 drilled stopper.
• Airlock setup: center hole is intended for standard fermentation airlock use.
• Small batches: useful for beer, wine, cider, mead, starters, and trial fermentations where the size fits.
• Spare part: worth keeping on hand when changing vessels or replacing worn stoppers.

Fit and Sanitation Notes

Match the stopper size to the vessel before brew day, then clean and sanitize both the stopper and airlock before installing them on a filled fermenter. For vigorous fermentation, confirm the airlock has enough capacity or switch to an appropriate blowoff setup.

For more vessel closures and fermentation supplies, browse our fermenters and accessories or brewing equipment collections.