30-37mm Tapered Bung with 10mm Hole

A versatile fermentation bung designed to give you flexible options during active fermentation. The tapered design fits a wide range of demijohn sizes, while the 10 mm bored hole is ideal for standard airlocks to keep oxygen out while allowing CO₂ to escape.

At the wider end of the bung, a 15mm recessed cavity allows 15mm OD blow-off tube (such as our 12.5mm ID Vinyl Tubing) to seat securely. This makes it easy to switch from a standard airlock to a blow-off setup during vigorous fermentations, helping prevent messy blowouts while maintaining a sealed system.

The tapered profile ensures a snug, reliable seal across most common smaller demijohns. It will also fit the Handcraft Supplies 5L Wide Mouth Demijohns. The bung material also adheres better to glass than a standard silicone that can become slippery and pop out.

Suitable for Demijohn Sizes:
 5L with Flip top

Height: 38mm

Bore Diameter: 10mm

Diameter (Large Taper): 37mm 
Diameter (Small Taper): 30mm