Flour (whole wheat, rye, spelt, chickpea, other)
Warm water (or tea)
1 jar of 800-1000 ml
A clean cloth
The natural yeast takes a few days or a week to grow. Start by mixing 3-4 tablespoons of flour and a little warm water in the jar. Form a kind of liquid dough (more liquid than cake dough). Cover the jar with the cloth, tie it with an elastic. Leave the jar in a warm place without drafts.
Stir the yeast 2-3 times a day, always with a wooden spoon. Feed morning and evening with 1 tablespoon of flour and warm water so that the yeast keeps the same consistence.
The third day small bubbles will appear on the surface of the leaven which already smells a little sour. Sourdough bacteria developped (compilation from a lactic acid bacterium called lactobacillus and a fungus, both noble).
On the fifth day, the natural yeast begins smelling like dough or baker yeast. The bubbles are larger. The sourdough is ready. If not used immediately, keep feeding the bacteria the same way. When using, leave a little leaven to make a new dose. The yeast can be “put to sleep”. Just thicken it with a nice dose of flour until it is like a paste. Preserve in the fridge. “Wake” it back with lukewarm water and a dose of flour.
The sourdough is an excellent basis for healthy, homemade bread, crackers, cookies. It can be fed for years.