Using Sourdoughs and Starters

For bread to rise, some sort of raising agent — or leaven — must be used. In most cases, this will be yeast, or perhaps bicarbonate of soda (baking soda), but it is also possible to initiate the fermentation process naturally, by the action of wild yeasts, present in the air, on a medium such as flour or potatoes. When this is done, the mixture that results is called a starter.

There are two basic starters: a natural leaven and a yeasted starter. The former uses only airborne yeast spores, which create a lactic fermentation, as when milk turns sour. A yeasted starter includes a small amount of baker’s yeast to kick-start the fermentation and develop a desired strain of yeast.