Keystones

Keystones are single-use plastic cask closures designed to seal the keystone hole, the smaller of the two openings on a cask head and the point through which beer is drawn during dispense. They are an essential consumable in cask-conditioned beer production, providing a secure and hygienic seal during filling, conditioning, transit, and cellar storage prior to tapping.

At the point of service, the keystone is pierced by a tap or extraction device to allow beer to flow. Keystones are manufactured from food-grade plastic and are designed to hold a reliable seal under the pressures and handling conditions typical of cellar environments, while remaining straightforward to pierce cleanly without fragmenting or contaminating the cask contents.

As single-use components, keystones avoid the cleaning and inspection burden of reusable alternatives and eliminate the risk of flavour carry-over between fills. They are compatible with wooden and plastic casks across all standard sizes and with standard cask tap and tapping equipment.