#8.5 Drilled Rubber Stopper (Bung) for Fermentation

#8.5 Drilled Rubber Stopper for Fermentation

This #8.5 drilled rubber stopper is a fermentation bung for compatible vessels that need a secure stopper and airlock closure. Use it with carboys, jugs, or other fermentation vessels that specifically call for a #8.5 drilled stopper.

The center hole is intended for a standard fermentation airlock or compatible inserted fitting where the stem fits correctly. A reliable stopper fit helps keep the fermenter covered while letting carbon dioxide escape through the airlock during active fermentation.

Best Uses

• Compatible vessel closure: fits vessels sized for a #8.5 drilled stopper.
• Airlock setup: center hole supports standard airlock use when the airlock stem matches the stopper opening.
• Fermentation projects: useful for beer, wine, cider, mead, starters, and small batch test fermentations.
• Replacement part: a practical spare when an older stopper is cracked, loose, stained, hardened, or difficult to sanitize.

Fit and Sanitation Notes

Match the stopper number to the vessel before filling. The stopper should seat firmly without being forced so far into the opening that removal becomes difficult. Clean and sanitize the stopper and airlock before use, then check that the bung stays seated once fermentation becomes active.

For vigorous fermentations, confirm the airlock has enough capacity or use an appropriate blowoff setup. For more vessel closures and fermentation supplies, browse our fermenters and accessories and wine making equipment collections.