Sourdough, Wild Bread of the West -- The Sunset Cookbook

Photo Courtesy SunsetSince California's gold mining days, sourdough has been a Western staple, delighting generations with its tangy flavor in breads, pancakes, and other baked foods. The West didn't invent sourdough, of course. This style of baking goes back to the ancient Egyptians, and Europeans have baked with sourdough starters (called levain, in France) for centuries.

How Sourdough Works

A sourdough starter is a portion of dough that is allowed to ferment. When this happens, the wild yeast and bacteria in the flour, in the liquid, and even in the air break down natural sugars and produce carbon dioxide, which enables bread baked with the starter to rise. As it ferments, the starter also produces acidity-in the form of lactic acid and some acetic acid-creating the "sour" in sourdough.

Starters vary from place to place (because wild yeasts are different everywhere) and baker to baker. The ones that developed in the San Francisco area were uniquely sour. In fact, the bacterial strain that's responsible for that sour flavor was eventually identified and named Lactobacillus sanfranciscensis in honor of San Francisco.

Once established, a starter can be kept going for decades. Boudin Bakery, founded in San Francisco in 1849 and still operating, traces its sourdough starter to one begun more than 150 years ago by Isidore Boudin. (The Boudin starter was borrowed, so the story goes, from one of the actual "sourdoughs"-the name given to gold miners because they relied so heavily on sourdough starters for bread baking out in the gold fields.)

A Bread Revolution

In the 1980s, sourdough helped fire up an artisanal bread–making revolution when Steve Sullivan and his wife, Susie, founded Acme Bread Company in Berkeley, California; to create the leavener for their European-style levain bread, which sets the standard for artisan bread in America, he created a starter inoculated with wild yeast from wine grapes.

Sourdough has been a standby at Sunset since 1933, when we published the first recipes. However, we discovered that capturing the right bacteria and yeasts to establish a good starter could be hit or miss-some mixtures never fermented at all, while others were weak or inconsistent. In 1973, staff food writer Kandace Reeves, working with microbiologist Dr. George K. York from the University of California, Davis, finally hit upon a truly dependable starter using yogurt.

Make Your Own Sourdough Bread

Sunset's Reliable Sourdough Starter
As with a classic starter, ours ferments flour and liquid -- milk, in this case -- with some yogurt, already packed with helpful bacteria to get things off to a good beginning. Yogurt also produces a very active, bubbly starter and gives a wonderful zesty flavor to the bread. After a few days' incubation in a warm place, the bacteria multiply to break down sugars in the flourand milk and give the characteristic sour smell and tang, and the starter is ready to use. Despite its terrific souring qualities, yogurt-based starters don't always have a reliable yeast component (their high levels of acidity can inhibit yeast's gas production), so we add dry yeast when baking. For best results, use milk (nonfat or low-fat for tangiest flavor) and yogurt that are as fresh as possible (check the sell-by date) and use them right after opening.

Sourdough French Bread
When Sunset published this recipe in 1973, the long, slender baguette was the onlyshape sourdough bakers were interested in. Professional and home bakers have branched out to additional forms, but the baguette remains the classic.

Sourdough California Apricot Bread
This recipe from reader Nell Rogers Lane of Novato, California, combines two California culinary treasures-sourdough and apricots.