Fermentation bung with size 4 hole (Ø 45 mm) - for 5 to 10 litre demijohn, with airlock

Fermentation Cap - Fermentation cap with hole, size 4 (inner Ø 45 mm)

This perforated cap fits onto the neck of a glass carboy to allow for the insertion of an airlock (gas bung). It lets the CO2 produced during fermentation escape while preventing air, dust, and insects from entering, thus protecting the fermenting must. An essential accessory for making homemade wine, cider, or fermented fruit juice.

Features

• Type: perforated fermentation cap, for airlock
• Inner diameter: 45 mm (size 4)
• Suitable for 5 to 10-liter glass carboys
• Packaging: 1 piece

How to choose the right size

Measure the inner diameter of your carboy's neck before ordering. Size 4 corresponds to a 45 mm neck and is suitable for 5 to 10-liter containers. For smaller carboys, from 2 to 5 liters, choose size 3 (Ø 35 mm); for 10 to 15 liters, choose size 4A (Ø 50 mm). This version is perforated for an airlock; there is also a version without a hole (solid cap) for sealing before or after fermentation.