In 1873, the manager of an ironworks in Söderfors, Sweden, was about to retire. When handing his responsibilities over to the next manager, he worried about one issue in particular: the future of a beer barrel.
This was not just any barrel, he explained in the letter to his successor. This was a barrel he had been given by the previous manager when he himself took over the ironworks half a century before, in 1820. In fact, he wrote, the barrel still contained beer from when it was first filled—in 1794.
What the retiring manager wanted was for his successor to continue taking care of this barrel. To do so, every other year, he needed to pull off half the barrel’s contents for drinking, then brew new beer to refill the barrel, and “well maintain it.”