The production of coarse grain bread is more complex and technologically more demanding than the production of mixed grain bread from flours. As a rule, several precursors are used in the form of sourdough, soaked grain, hot soaked grain and boiled grain. Often soaked bread is added and processed. The necessary swelling and bulk fermentation times are largely determined by the granulation of the coarse grain used. As a rule, the sourdough process must include a coarse grain sourdough in order not to fall below the 90 % proportion of coarse grain in the total proportion of milled grain products required by the guidelines.
