Wolfgang Kunze's "Technologie für Brauer und Mälzer" is a wonderful book. It describes in minute detail how to run a VEB brewery. He's pretty good on the technical stuff. Which explains why a later version of this book, produced after reunification, is still a standard text.
This information comes from pages 198 and 199 of the 1961 edition.
It's always the Dickmaische which is boiled. The Dunnmaische or Lautermaische is very enzyme rich as the enzymes are soluble.
The amount of the mash to be boiled (Kochmaische) is one third and two thirds of the total. [There then follows a series of formulae for calculating the exact amount]
hl Kochmaische = (desired rise in temperature * hl total mash)/(90 - Restmaische hl)
Restmaische = total mash - Kochmaische
Example: you've got 130 hl of mash at 50º C that needs to be heated to 64º C
hl Kochmaische = (14 * 130)/40 = 45.5 hl
The time the mash should be boiled varied, depending on the type of beer:
pale beer - 10-20 minutes
dark beer - 20-30 minutes
adjunct mashing - 30 - 40 minutes
The Kochmaische should be pumped into the Restmaische (and not the other way around) so that the temperature of the Restmaische rises slowly and the enzymes aren't destroyed.
This is the oldest method of decoction.
einmaischen 35º C
1st Kochmaische 50º C
2nd Kochmaische 65º C
3rd Kochmaische 72-74º C
Triple decoction is very intensive, time-consuming and requires much more energy than double or single decoction. The gains are very small in comparison to the extra effort and consequently is no longer much practised.
einmaischen 50º C
1st Kochmaische 65º C
2nd Kochmaische 72-74º C
You may have noticed that the triple decoction is very similar to the Munich method I told you about earlier. Don't worry about all the entries for this series looking very similar. The Augsburg method is very different. That makes use of Saz. Never heard of Saz? Don't worry. Neither had I before yesterday.