Warm Water, Quick Rise

• For most of its 6,000-year history, bread-baking was a chancy thing. The yeasts could be collected wild from the air, skimmed from a vat of beer or even preserved from batch to batch by saving a piece of the old bread. This changed in the late 19th century, when French scientist Louis Pasteur isolated and identified pure strains of yeast. Commercial production began soon after, and it became possible for home bakers to start and finish bread reliably in a matter of just a few hours. This technique required warm water and a warm, draft-free place where the yeast could ferment readily.

That First Fermentation

• Most of the sugars in your flour are bound up in the form of starchy carbohydrate molecules, which are indigestible to yeasts, but enough of these starch granules are broken during milling to feed the yeasts. They convert the sugars into both alcohol and carbon dioxide, then divide to create new yeasts that repeat the process. High temperatures provide fast yeast development, but the faster the yeast digest their sugars the more alcohol they create. This produces bread with a coarse texture, sour flavor and poor storage life. At a more moderate temperature of around 80 degrees Fahrenheit, the bread rises briskly without producing unpleasant flavors.

More and Better Sugars

• The relatively modest quantities of available sugars in the bread dough limit the yeast's growth, so bakers often add sugars in the form of milk, honey or ordinary granulated sugar. This is effective, though the resulting loaves are rather bland. Artisan breadmakers take the alternative approach of slowing down or "retarding" the dough's rise, by keeping it cold. That permits time for bacteria and enzymes in the flour to break down the starch granules, freeing up the natural sugars that are already present in the grain. This produces bread with more complex and subtle flavors, and a characteristically dark golden crust. Cold-rising doughs often start with cold water, rather than warm.

Starting Cold

• If you mix up a warm bread dough and then refrigerate it, it rises briskly until the refrigerator's chill reaches the middle of the dough ball. You can counter this by dividing the dough into small pieces, but it's easier to just begin with cold water. The yeasts will still reproduce and leaven the bread, but it can take 12 to 24 hours just to complete the initial fermentation. This creates ample opportunity for flavor development, and the dough also grows strong, elastic gluten strands that result in a pleasantly chewy crust and good crumb development. Finish your bread by letting the dough come to room temperature, then shaping your loaves and giving them a final rise as you normally would.