"guiding a natural fermentation demands considerable knowledge of the hazards which biological life undergoes and  resembles the role of a mother, in order to obtain a product close to perfection by respecting a harmonious chronological order. " "It is an act which gives life".

 

(Guide De L'Amateur Du Pain (1981) - Lionel Poilâne, the late celebrated Parisian baker)

                                 Levain/Natural Fermentation

What is a naturally-fermented bread?

A mixture of flour and water is kept under certain conditions for several days and enters into a natural fermentation - properly maintained the fermentation will stabilise and only two species of bacteria will remain living - yeats and acid-forming bacteria. This is the starter (sourdough) culture that can be now used to make bread - the "levain". It is the original way to make risen/leavened bread.

So naturally fermented bread has a yeast fermentation (predominantly responsible for causing the bread to rise) and an acid fermentation (enhances nutritional and keeping properties, makes the flavour more complex).

Yeast Fermentation

"Yeast" bread has only a yeast fermentation and comes from a yeast culture which is produced in factories. Naturally fermented dough contains naturally occuring yeasts which are predominantly found on the cereal grains.

Acid Fermentation

The acid fermentation causes an acidity (from which the word "sour dough") which when poorly controlled results in sour, heavy bread. Unfortunately many people assume that sourdough bread is by nature sour and heavy.

Unique "Levain" culture

Each levain (sourdough culture) is unique and how the baker looks after it determines the type of bread he/she will produce. It creates diversity amongst bakers. It makes a baker worthy of the term "artisan".

Natural Fermentation in France

In France a natural fermentation is called a "levain naturel".

Naturally fermented bread began to disappear in French cities in the late 19th century - it was being replaced by "yeast" fermentation thanks to innovations in yeast production and breadmaking techniques that came from Vienna. By the 1930s almost all of the naturally-fermented bread is produced in the countryside. Naturally fermented bread becomes rare - so rare that when Jan Demaitre began teaching naturally-fermented breads in the French National Baking School (INBP) in the 1970s some of the teachers did not believe it was possible to make a satisfactory bread that was 100% naturally-fermented.

Nowadays thanks to scientific research and influential bakers like Marc Dewalque and Lionel Poilâne there is a revival in naturally-fermented breads. 

Naturally Fermented Baking

A well made yeast bread can be of excellent quality but bread really comes into it's own when it is naturally-fermented. The most celebrated bakers and breads use this natural fermentation.  

Natural fermentation requires a lot more attention and work on the part of the baker. The process for making the bread becomes longer and more complicated. The bread is subject to variations as the "levain" is a living entity changing with the seasons and the environment around it.