Vented Rubber Demijohn Bung Cork with Cap, 43mm/ 40mm

This white rubber bung cork has a 43 mm / 40 mm diameter, a central vent hole and attached lock-cap, making it the ideal airtight seal for 5L demijohns—whether fitted with a swing-top cap or a plain neck. Please note: it is not compatible with the demijohns sold in our store.

Moulded from premium, food-grade rubber, it flexes to form a secure, leak-proof fit; the precisely drilled vent hole accommodates standard airlocks to release fermentation gases while keeping contaminants at bay; and the snug-fitting cap seals the opening when not in use. Its smooth surface ensures effortless installation and quick cleaning, making it indispensable for home brewers, winemakers and laboratory technicians alike.

Key Features

• Integrated vent hole: Precisely drilled at the centre to accept standard airlocks or other fermentation fittings, allowing gases to escape while excluding contaminants.
• Lock-cap closure: Snug-fitting cap seals the vent hole when not in use, offering extra flexibility between batches.
• Durable & flexible: High-quality rubber construction conforms effortlessly to the neck of your container for a reliable, leak-proof fit.
• Hygienic & easy to clean: Smooth surface makes installation and maintenance a breeze—perfect for repeated use in home brewing, winemaking or laboratory applications.