Biga is a type of starter used to make traditional Italian breads. In Italy, the term is used to refer to sourdough sponges, collectives of wild yeast, and other starters. If an Italian recipe includes this ingredient, cooks should consult the recipe to make sure that they are using the right type, since the term is so all-encompassing. When a biga is used, bread is lighter, with bigger holes and a more moist crumb. The result is a classic Italian country bread, a popular baked good in many parts of the world.
In some parts of Italy, the biga is known as “la madre,” or “the mother,” a reference to the idea that it is the mother of the bread. Making this starter is a type of pre-fermentation, promoting developing and maturation of the yeast. Since the yeast is more developed, the bread made with a biga takes longer to rise, but it also has a more complex and evolved flavor. As with many pre-fermentation processes, it takes practice to make.
A classic biga is made from the unsalted dough of the previous day's bread. The cook simply scoops a wedge of dough out before salting or sweetening it, and sets it aside tightly wrapped in a cool place overnight. Putting it under refrigeration will slow the development of the yeast, while a biga can mature in a warm place in around six hours. The next day, the cook uses it in a bread recipe, pulling another chunk of dough out to repeat the process. When this system is used, the biga will need to be periodically refreshed, as it is not collecting new yeasts and the colony can become weakened.
Other cooks make a large batch of dough intended for use as a biga. It starts with dissolving 0.5 teaspoon (about 1.5 grams) of yeast in 0.75 cup (118 ml) of water and allowing the mixture to sit until foaming before adding around 2.5 cups (85 grams) of flour. The dough is loosely kneaded, and it will be more dry and less elastic than regular bread dough. It can be left in a warm place to mature, refrigerated for up to three days, or frozen for up to three months.
Many Italian breads such as ciabatta are made with a biga base. As the starter rests, the yeasts inside multiply, and they also form complex flavors and aromas which enhance breads made with it. The flavor and texture of a biga-based bread is significantly different than an ordinary yeast bread, and some consumers appreciate the additional complexity.