One of the most exceptional and puzzling glass container shapes is known in German as a Guttrolf. The name is derived from the Latin „gutta“, meaning drop and „guttura“, meaning the larynx, which explains what it was used for: to allow liquid to flow drop by drop into the larynx.
The Guttrolfs in the museum of glass are the centrepiece of the collection. During the 1940s they are what inspired the museum founder Dr. Hans Löber to begin collecting glass. The foundation of the museum in 1976 goes back to a five-cylinder Roman jug dating from the third or fourth century. The glass physicist just couldn’t work out how it had been made and during his search for a solution he collected the most comprehensive Guttrolf collection in Germany, comprising over 30 examples from various different countries dating from the fifth to the 19th century.
In collaboration with the master glassblower for glass apparatus, Leonhard Macholdt from Wertheim, Löber revived the old forgotten glass production techniques. The ability to blow a several cylinder Guttrolf using a blowtorch was one of them and a document about the glass foundries in Spessart dating from 1405 was decisive in finding a solution to the technical problem. It describes a daily production of 300 small beakers and 200 Guttrolfs, which went against the complex smelting and mounting technique of the separate cylinders that had been supposed up until that point. So, there must have been a simpler way. A round cylinder can be squeezed together into a square shape, and the air is sucked out instead of being blown in which makes the walls of the glass fall together, so that altogether five cylinders are created. During reheating the shape of the glass can be contorted so that it looks as if five cylinders were created in neck.