Pistorius Vessel @museum.de

M: What you're looking at here is a Pistorius vessel. The design was invented in 1817 by one Johann Pistorius. This is what you need to know about him:

F: Johann Heinrich Leberecht Pistorius was born in 1777 in the town of Loburg, in present-day Saxony-Anhalt. He later lived in Weissensee – which was in Prussia at the time and is now a district of Berlin. On the 21st of March 1817, Pistorius was granted a patent giving him the …

M: "express right to employ and manufacture a curious distillation apparatus."

F: Pistorius was particularly interested in the potato – and the question of how to distil spirits from it.

M: Prussia and potatoes? Somehow, that rings a bell!

F: Of course, Frederick the Second, King of Prussia.

M: Also nicknamed "Old Fritz".

F: As king of Prussia, he issued several decrees that became known as "potato orders". Probably the most famous of them dates to 1756 and was designed to increase the potato's appeal among Frederick's subjects and promote potato-growing, given that war and crop failures had led to famine.

M: "In our other provinces, the planting of potatoes, as a tuber crop in diverse manner most beneficial to both man and beast, has been earnestly recommended by us in our own person.”

F: But back to Pistorius. Starting in 1817, he developed a method of turning the highly praised potato into high-proof schnapps. Pistorius incorporated a special tank into his apparatus: it works like a condenser and produces improved fractional distillation. The tank, known as a Pistorius Vessel, ensured that the water vapour condensed, while the spirit remained in vapour form and the alcohol content continued to rise – up to 70 per cent proof.

M: With his invention, Pistorius made it so cheap and easy to produce brandy that almost all of Prussia's agriculture reorganised virtually over night. The potato fields extended as far as the eye could see. And Berlin rose to become the worldwide centre of the liquor trade. Meanwhile, the potato mash was fed to the livestock, and as a result, Prussia experienced an extraordinary boom in pork production.

F: The potato, previously the staple diet of the poor, was now a crucial raw material.