Today in 1874, US Patent 148297 A was issued, an invention of Ole Heggem, for his “Improvement in Casks for Preserving Beer.” There’s no Abstract, although in the description it includes this summary:

That which I claim as new, and desire to secure by Letters Patent, is —

1. The combination, with a beer-cask, of a collapsible bag, capable of filling the entire interior of said cask, and secured to the interior of the cask at its mouth, by means of the head of the cask being set in against the edges of said bag, lying between the edges of the head and the staves, said head being provided with an open vent, as specified.

2. In combination with the bag and cask, the head, provided with a vent-hole, guarded by the plates at each side, and having the grooves 0, as specified.