Proofing Yeast

If there is any doubt about whether or not the yeast is still alive, it should be "proofed" before it is added to the other ingredients. Proofing is accomplished as follows -

1. Combine the yeast with warm liquid and a small amount of flour or sugar.

2. Let the mixture rest at room temperature until a thick surface foam forms.

3. The foam indicates that the yeast is alive and can be used. If there is no foam, the yeast is dead and should be discarded.

Sourdough starters are used to leaven a variety of country-style breads, biscuits and even pancakes. Sourdough starters are essentially cultures produced by blending flour and water. This mixture is then inoculated with an existing yeast, or is left exposed so that wild yeast, naturally present in the air, will begin the process of fermentation.

Starters can be kept alive for extended periods, by replenishing the flour and water as some of the starter is removed to prepare baked goods, This long life has become the stuff of legend in some bakeries where the culture has been kept alive for years, even decades.

Different parts of the world have different types of wild yeasts, which lend a particular flavor to the sourdough starter. In addition, the degree of sourness considered appropriate varies from one region or country to another. San Francisco sourdough is different from that produced in France.