Sourdough Culture

Tart, tangy sourdough bread encourages a healthy digestive system and inspires mindful cooking in its dedicated makers.

sourdough bread

Sourdough bread's natural probiotic properties make it easier to digest and have less impact on blood sugar than other yeasted breads.

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Sarah Owens’ relationship with sourdough starter began in a used bookstore. “I picked up this hokey old cookbook from the ’70s called Adventures in Sourdough,” Owens says. “It had a chapter on how to take your starter camping.”

Owens bought the book partly on a whim (it was only 50 cents), but also because she had been suffering from disruptive digestive issues, and had started making fermented foods as a way to help soothe her digestion.

The results were transformative, not just for Owens’ health, but for her professional life, too. Now a baker and award-winning cookbook author (Sourdough, published last year by Roost Books), Owens says her kitchen experimentation also changed her life by helping her become more mindful. “I think it forced me to slow down and observe what’s happening in the moment,” she says. “It sounds new-agey, but it’s so important, and something we take for granted.” 

How it Works

Sourdough bread is the product of natural fermentation between wild yeast and lactobacilli present in our environment—the same beneficial bacteria found in yogurt and cheese.

The basics of creating sourdough starter involve mixing flour and water, and leaving the mixture to ferment. The yeast and bacteria latch on to the broken-down sugars in the flour, creating probiotic byproducts as well as flavor compounds, such as the acetic acid that makes sourdough tangy.

In addition to bread, sourdough starter can be used to make other baked goods, including crackers, cakes and pastries. In her cookbook, Owens writes that the acidity of sourdough culture pairs well with various flavors, including chocolate, and adds extra tang and texture to pie crusts.

Sourdough’s Health Benefits

One of the byproducts of fermented foods such as sourdough is lactic acid, which can aid digestion, control intestinal infection and may even inhibit some types of cancer. Lactic acid breaks down the gluten in flour, which allows the body to digest it more easily, and helps us absorb important nutrients such as iron and B vitamins. That sugar breakdown also means sourdough doesn’t impact blood sugar levels as much as conventionally yeasted breads, which have no probiotic component.

The Care and Keeping of Sourdough Starter

Because sourdough starter is alive, it must be fed regularly to remain active.

“A healthy starter is one that is continually fed,” says Susan Miller, a baking expert at King Arthur Flour. Miller says a regularly used starter should be kept at room temperature and fed twice a day. Less frequently used starters can be kept in the fridge and fed about once a week.

Sourdough starters can be endlessly renewed, and even passed down through generations. However, Miller notes, while the lore surrounding heritage starters can be entertaining, it has no bearing on the final product. Variations in feeding times, flours and hydration determine the characteristics of the resulting bread. “By the time you have it in solid, healthy shape, there’s probably not much left from even a couple of weeks before, let alone generations before,” Miller says. “I tell people to focus less on where it came from, and more on how you’re treating it now.”