Seems a curious and interesting fact for both above groups:
traditionally russian so-called "improved" rye sourdough breads call
for rye malt and rye flour "no-sparge" mashing.
This mashing stage ("zavarka") takes about 1.5-2 hours (for some breads
even more) at 62-65C and carried out by adding "striking" boiling water
to the rye flour and malt grains. In industry this stage is performed
in mashing tans that have a tubing system for heating/cooling the mash.

Afterwards the mash should cooled down to about 30C before starter is
added and fermentation starts. I didn't find the explanation (and maybe
somebody has it) for the recipie requirement that the cooling to take
5-7 hours and not as in All-Grain brewing where boiled wort should be
cooled as quickly as possible to improve cold break and avoid
contamination.
Even at my quite hot climate when average temperatures now of about
24-25C the cooling takes about 3 hours. Yes, it's 4kg and not 4 tons
but the recipie sounds like cooling is a part of a process and not a
constraint.

Anyway the bread is gorgeous...