Today in 1891, US Patent 460291 A was issued, an invention of Friedeich Jung, for his “Apparatus for Heating and Pitching Barrels.” There’s no Abstract, although in the description it includes these claims:

The object of my invention, as described below, is to burn out beer-barrels with a direct flame and to remove the danger of explosions, which are still of frequent occurrence in pitching barrels. It is a notorious fact that the latter far more frequently occurs especially when barrels are pitched by the application of hot air or steam than when an open flame or direct fire is employed. The explosive gases are generated and the explosion is produced generally on account of a want of atmospheric air in the barrel.