Homemade Yeast - cooking recipe

Ingredients

flour
water

Preparation

Make a thin batter of flour and lukewarm water; let it stand in a warm place until it ferments and is full of bubbles.
Two cups of this liquid yeast is equal to one cup of old yeast.
Yeast is good when foamy and full of beads, has a brisk pungent odor and has snap and vim; it is bad when it has an acid odor, is watery and has a thin film on top.