What is Sourdough?
There is a common misconception that ‘sourdough’ refers specifically to a particular flavour or bread, often a type of white bread that has a distinct sour taste profile.
Sourdough, actually, refers to any bread that has been made with a natural culture of wild yeasts and lactic acid bacteria (known as a sourdough starter) that is used to slowly ferment bread dough.
Most types of bread can be sourdough, whether it be crusty loaves, fluffy brioches or laminated pastries like croissants - breads that many wouldn’t associate with being sour at all. Some people are, therefore, of the opinion that the name ‘sourdough’ is a little inaccurate or misleading, and that sourdough should perhaps be re-named ‘naturally fermented bread’ to distinguish it from bread made using baker's yeast (aka commercial yeast/fast-acting yeast/dry yeast).
Sourdough bread in its purest form only contains three ingredients: Flour, Water, and Salt.
The sourdough starter that is used to leaven (rise) bread dough is made using a mixture of only flour and water and is produced by harvesting (or capturing) wild yeast and bacteria that are naturally found in the environment (from the air and the surface of grains). This means that the particular species and strains of microorganisms found in a sourdough starter varies a great deal between regions and bakers, and each culture is believed to have its own unique characteristics. In fact, in 2013 a sourdough library was launched in Belgium where a collection of sourdough cultures from all over the world are being stored and studied (to find out more about the sourdough library click here). To date, studies have recorded over 700 strains of wild yeast and 1500 lactic acid species.
Some of the strains of yeast and bacteria found in a sourdough cultures are unique to sourdough cultures and are not found anywhere else.
Bread made with a sourdough culture is often referred to as ‘slow bread’ which describes the longer process in creating a loaf of bread compared to using a commercial yeast commonly used today that helps speed up the bread baking process.
Commercial yeast is made from a single strain of yeast isolated from a wild yeast culture for its ability to rapidly digest sugars and produce carbon dioxide.
Compared to bread made using commercial yeast, which may take as little as a couple of hours, the slow fermentation that happens in sourdough bread takes many more hours. Here, at The Farmhouse Bakery, our sourdoughs are fermented between 24-36 hours before baking.