When I first began researching the history of brewing, I kept coming across references to “pitched barrels” and “brewers’ pitch.” I had no idea what they were referring to! Was it some type of finings to clarify the brew? A special type of flavouring that went in barrels? It was all a bit of a mystery until I stumbled upon Julius Thausing’s book The Theory and Practice of the Preparation of the Malt and the Fabrication of Beer. In great detail he explains that brewers’ pitch is in fact tree pitch used to coat the insides of barrels, primarily barrels used to transport beer from one location to another. Barrel pitch was obtained from Conifera trees; larches, firs, pitch pines, etc. To obtain pitch, either the bark of the tree was peeled off, or incisions were cut into the tree. The resin was collected and boiled and constantly skimmed to remove the oil of turpentine that collected on the surface of the vat. The clean pitch was drawn off and sold as brewers’ pitch.
Thausing’s instructions on how to pitch a barrel – “The bung and plug having been driven in, the barrel is “knocked up,” i.e., the head hoop and first hoop are taken off, and the belly hoop is loosened if necessary; the head is then taken out… The barrel which is to be pitched must be dry; if necessary, a bundle of straw is burned in it for the purpose of completely drying it… The pitch is brought to the boiling point in an open boiler of sheet-iron or copper, which is bricked in over a furnace. The barrel is laid obliquely against a block of wood, the open side being somewhat raised, the necessary quantity of pitch is poured into it with a ladle, and thus is ignited by a red-hot iron. The head which has been taken out is turned towards the barrel, so that only sufficient air can enter for keeping up the burning, and the smoke can pass out. The pitch should burn briskly, because if the
smoke is not carried off well the beer will afterwards acquire a disagreeable, smoky taste…After a few minutes, the head is pressed tightly against it to extinguish the fire, the pitch is scraped out of the grooves of the chime, the head is quickly put in, the hoops are driven up, the barrel is turned over several times to distribute the pitch uniformly, and finally the plug is knocked out to allow the air and smoke to escape. The barrel must then be rolled for some time until the pitch has become cold, and then the bung is also taken out.”
By the early 1880s when Thausing wrote his book, pitching machines that used steam to melt the pitch and roll the barrels had become quite common in commercial breweries. Other than the obvious advantage of a reduction in labour, the machines also had the benefit of being able to pitch the barrels without having to take them apart. This saved considerable wear and tear on the barrels and reduced the amount of pitch needed per barrel. Thausing calculated that one kilogram of pitch per hectoliter (26.4 gallons) was sufficient to coat the inside of a new barrel.
In the next post – another largely extinct method of barrel preparation – sulphuring!