The following text is translated from “Pilsner Bier im Lichte von Praxis und Wissenschaft” written by Professor Eduard Jalowetz in about 1930. The book I have is itself a translation of a Czech translation of a German original. It is published by Euroverag GmbH for Pilsener Urquell.A number of the terms in this description are problematical. I draw attention to them where I'm not sure. All temperatures are given in degrees Réamur, a now obsolete temperature scale. Like Celsius, the freezing point of water is 0°, but water boils at 80° R, so to convert Réamur to Celsius, multiply by 1.25.
The mashing technique is the “triple mash process” that was formerly used inmost breweries, in particular in Bavarian breweries that had direct firing, but with the very significant difference that a very thin mash, so that the sparge from a 12% [Brix] beer is only 12 to 12.5%.
Briefly, the mashing process is the following:
This one appears to be the one that is fired; the other one is referred to in the German text as “Pfanne” (pan). The mash starts cold and is heated to 27° to 28°R [34° to 35° C] in ten minutes with hot boiled water from the pan of the simple kettle.
It's not clear what “simple kettle” (“einfaches Sudwerk”) means. Elsewhere there is talk of two separate kettles.The first mash then runs back into the pan and due to the water remaining in the pan, the temperature rises to about 42°R [52° C]. In about 13 minutes the mash is heated to 50°R [62.5 °C] and in 20 minutes from 50° to 60°R [72.5°C] and saccharified in about 8 minutes. Shortly after that, about 12 minutes, the mash boils for 30 minutes.