Unfortunately, I have no Ortiz book and have no idea, what is it
"porridge bread".
Is it of Limpa batter bread style like Ed Wood describes?
The technique for Borodinsky bread is an elaborated method for a kind
of rye breads (60% rye and more) called "improved" and made by keeping
rye/rye malt mix for about 2 hours at temperatures 62-67C (about 150F)
that is mashing in essence: saccarification of rye flour starches by
rye malt amylase enzymes. Mashing is a main stage of making beer.
See the thread
http://groups-beta.google.com/group/...31258f400eab2c

and www.howtobrew.com

Russians and German mainstream idea (read correspondence with Michael
Ganzle in D. Wings book and here, at the group) is that because "white"
wheat bread shouldn't be acidified substantially; there is no need for
use of sourdough starters but usual baker's yeast. Not as French or
Italians think! Recently I have found hints that "off the beaten track"
there are sourdough techniques for wheat bread in russian technical
literature but meantime have nothing tangible just references.
"A 100%-rye porridge bread made without yeast that bakes for 7 hours"
reminds Pumpernikel, doesn't it? But can't say it's not my cup of
tea/slice of bread: I limited myself to russian breads only.

Leonid