The history of sourdough is already several thousand years old. By all accounts it appears that both bread and beer were made in ancient Egypt some 1000BC. In the tombs of the Pharaohs, along side other artifacts, bread remains were found having a Ph value of between 4 and 5, indicating that the bread was a type of sourdough.
Sourdough is a cereal-based starter culture containing a colony of microorganisms including yeast and lactobacilli (lactic acid bacteria). Most rye-based sourdough starters are used in baking; they can, however, also be used for brewing beer. The fermentation process begins when milled grain and water are added to a starter, or mother culture, and left to rest at a constant temperature. When flour comes into contact with water, the naturally occurring enzyme amylase breaks down the starch into sugars, which the natural yeast contained in the sourdough can metabolise, forming lactic acid and Carbon dioxide (CO2), thus leavening the dough.
Through the fermentation process the micro-organisms contained in the sourdough multiply, breaking down the components of the grain, such as Phytic Acid, which are more difficult to digest. Phytic acid is a known as a food inhibitor which prevents the bioavailability of the grain from being absorbed into the body. By allowing a sourdough sufficient time to rest, the enzymes break down the Phytic acid and the minerals contained within the grain, including Iron, Calcium, Magnesium and Zink, can be more easily absorbed.
Rye has a high quota of phosphorus, calcium, iron as well as vitamines B and E. Sourdough is multi-talented, facilitating a better bake whilst rendering the resulting bread more easily digestible, so that even those with intolerances and digestive disorders are able to savour and relish wholegrain bread.
Even the sticky protein gluten becomes easier to digest thanks to the activity of microbes during the fermentation process, which alter and weaken the gluten’s chemical structure. There is no need to use baker’s yeast as, during the maturing process, the sourdough forms its own yeast. The sourdough’s naturally occurring yeast is less vigorous than baker’s yeast which is why obtaining a satisfactory rise requires more time and patience.