only 0.25% of flour weight, barely a gram per pound/500 gm is needed (One gram still contains millions of yeast cells.) As a general rule, the less prepared yeast goes into the dough, and the longer dough is allowed to rise, the better the flavor of the finished bread This is because the concentrated yeast has its own somewhat harsh flavor, and because the process of fermentation generates a variety of desirable flavor compounds (p 543) Durum Breads Durum wheat flour forms an inelastic dough that doesn’t rise well, but has nevertheless been used to make dense, distinctively flavored, golden breads in the Mediterranean region for thousands of years Durum flour absorbs nearly 50% more water than bread flour does, a fact that is part of the reason for the longer shelf life of durum bread Starters A general method for incorporating yeast into bread dough that maximizes the effective fermentation time and flavor production is the use of pre-ferments or starters, portions of already fermenting dough or batter that are added to the new mass of flour and water The starter may be a piece of dough saved from the previous batch, or a stiff dough or runny batter made up with a small amount of fresh yeast and allowed to ferment for some hours, or a culture of “wild” yeasts and bacteria obtained without any commercial yeast at all This last is called a “sourdough” starter because it includes large numbers of acid-forming bacteria Starters go by many names — French poolish, Italian biga, Belgian desem, English sponge — and develop different qualities that depend on ingredient proportions, fermentation times and temperatures, and other details of their making Sourdough breads are described on p 544 ... maximizes the effective fermentation time and flavor production is the use of pre-ferments or starters, portions of already fermenting dough or batter that are added to the new mass of flour and water... English sponge — and develop different qualities that depend on ingredient proportions, fermentation times and temperatures, and other details of their making Sourdough breads are described on p 544... mass of flour and water The starter may be a piece of dough saved from the previous batch, or a stiff dough or runny batter made up with a small amount of fresh yeast and allowed to ferment for some hours, or a culture of “wild”