The origin of the sourdough is dated to approx. 4000 BC. At that time, it was discovered that a mash of grain begins to ferment if it is left to stand for a longer time and develops aeration in this way. This property has been used since then to produce aerated and
digestible bread. There are indications and depictions that, in ancient Egypt, acidified bread was already being produced in large numbers. In the course of the 15th and 16th centuries, bread was then made with the help of beer yeast, which increased even more at the end of the 18th century due to the industrial production of the yeast. The use of sourdough was limited to the production of bread containing rye, as, in addition to the aeration, also the baking ability of the rye flour had to be guaranteed. Over the past years, sourdough has grown in importance once again, as it is associated with the original way of making bread (Brandt & Gänzle 2006).
Definition sourdough
A common and recognized definition of sourdough can be found in the “Leitsätze für Brot und Kleingebäck” (guidelines for bread and morning goods).
“Sourdough is a dough where micro-organisms (e.g. lactic acid bacteria, yeasts) from sourdough or sourdough starters are in an active state or can be reactivated. Following the addition of grain products and water, they are capable of forming acid continuously.” (Deutsche Lebensmittelbuch-Kommission DLMBK 2019).
If the sourdough is dried by means of thermic processes such as roller drying or spray drying, then a dried sourdough is spoken of.