What You Need to Know
A keystone is a small wooden or plastic fitting used in ale casks. For some years wooden casks have been effectively obsolete, with the majority now being aluminium or stainless steel, and a few sturdy plastic ones beginning to appear. Nevertheless, the standard tap is still designed to be hammered into yielding material, punching a hole as it goes. All modern casks, even the few wooden ones still in use, use a replaceable keystone to accept the tap.
Steps
- 1.
Cask-conditioned ale (United Kingdom): Traditional method for secondary fermentation
- 2.
Barrel-aged cider (France): Imparts woody character and allows natural carbonation
- 3.
Firkin-aged kombucha (USA): Modern adaptation for complex flavor development