Unlike the brewing records, it lists the brewing process in great detail. In particular, the mashing and boiling schemes. Things I had to just guess at before. Great, in the greater scheme of things. But it means that I have to rewrite all the Heineken recipes in "Blitzkrieg!".
Some of my guesses weren't far wrong. The Pis did have a double decoction, not much different from my guess. And I was correct about some numbers signifying the hop addition quantities. Which, weirdly, increase the later the addition. The timings I got wrong, however. Rather than 90 minutes, 60 minutes and 30 minutes, they were 120 minutes, 60 minutes and 20 minutes. Not so far wrong. I'm pleased that I got that close.
Beiersch is where I was the most wrong. That had a triple decoction. But most unexpected was that the kleurmout - a roasted malt similar to black malt - was added to the lauter tun around the time of the third decoction. No way I would ever have guessed that.
Here are the mashing details of a test batch of Beiersch. Where they were looking at the difference between using well water and mains water.