To bake sourdough is to make real bread truly from scratch. It's a near magical process to watch as a simply slurry of water and flour captures wild bacteria and yeast to produce a bubbly, living culture that's robust enough to leaven bread. True and authentic sourdough bread is near magical: deeply complex in flavor, fun to make and nutritious. Even more, it's an opportunity to connect and embrace the tradition of baking bread through the same process that's been used since grain was first cultivated tens of thousands of years ago.
What is Sourdough?
Sourdough is any bread or pastry leavened by a mixed culture of wild bacteria and wild yeasts. This mixture, also called a starter, levain or mother culture, is made by whisking flour and water together to form a slurry. This slurry, when kept at room temperature and refreshed regularly over about a week, will foster the growth of lactic-acid producing bacteria and wild yeasts.
Working together, these microbiota help to not only flavor traditional bread, but leaven it, too. Bakers typically use bacteria- and yeast-rich starters to leaven bread, but you can also use a them to leaven any yeasted dough including many pastries like cinnamon rolls, croissants, and some cakes. It can be made with whole-grain flour, high-extraction flour and white flour.
The naturally occurring wild lactobacillus bacteria cultivated in a sourdough starter give the bread its characteristic sour or tart flavor,
What's different about sourdough bread?
The biggest difference between traditional and artisan sourdough breads and the modern breads you find in the grocery store or might bake at home centers around its yeast. Yeast makes bread rise. And in traditional sourdough baking those yeasts are wild, and they come from the surrounding environment.
In modern bread baking, those yeasts are domesticated and typically come as dried granules in a packet you buy from a commercial yeast maker. The yeast in sourdough bread often contains more than one variety while the yeast in modern breads only contains one variety - saccharomyces cerevisiae, which is also used in beer brewing.
In addition, sourdoughs have a complex sour flavor that can range from very light to very strong. This sour flavor comes from lactobacillus bacteria in the starter culture. These bacteria metabolize the complex carbohydrates in flour and produce lactic acid, which gives the bread a distinct tartness.
Commercial breads and modern breads risen with packaged yeast lack this characteristic, and have a sweeter and less complex flavor. They also lack the rich and complex microbial diversity that gives true sourdough its flavor and many of its nutritional benefits as well.
What are the benefits of sourdough bread?
The clear benefit of sourdough bread is that it is delicious, with a richer flavor and more complexity than modern breads. It can be easily and affordably made at home, and it is a fun hobby to undertake: Making bread truly from scratch.
The bigger question you might ask is, "Is sourdough healthy?"
Traditional, slow-rise sourdough bread is generally a more nutrient-rich choice and easier on blood sugar regulation than modern bread. Its benefits rest in the symbiotic action of the bacteria and yeast that comprise a sourdough starter culture. The work of these microbes helps to make sourdough bread more nutritious with a lower glycemic load.
The mixed culture of wild bacteria and yeast that leaven sourdough bread make sourdough more nutritious. During the period in which sourdough rises, the lactobacillus bacteria in the culture metabolize the naturally occurring carbohydrates in the flour and release lactic acid. This lowers the overall glycemic load of the bread, while also improving its flavor and giving sourdough its characteristic sourness.
Further, the acidic nature of the dough helps to deactivate food phytate, a naturally-occurring substance in whole grains, pulses, nuts and seeds, that makes the minerals they contain difficult to absorb. When food phytate is deactivated or mitigated through sourdough leavening, the minerals in the flour become more readily absorbed by your body. So while sourdough baking doesn't increase the minerals in bread, it certainly increases your bodies ability to take advantage of them.
- It is a better source of minerals than modern bread. Sourdough sees an increase in the availability of magnesium, phosphorus (source), iron and zinc (source). As a result your body gets more absorbable minerals with every bite.
- It is lower on the glycemic index than modern bread. Because the carbohydrates in these traditional breads are pre-digested by the lactobacillus bacteria in the starter, who produce acid as a byproduct of fermentation, the glycemic load of these breads is typically lower than modern breads.
- It is rich in beta-glucan. Beta-glucan is a complex carbohydrate and prebiotic that helps support optimal cholesterol levels (source), blood sugar regulation and cardiovascular health (source), and sourdough breads are richer in this nutrient than modern breads.