What's so great about sourdough?
Everything, actually. While standard supermarket bread is an inflammatory junk food, naturally leavened, whole-grain, ancient-grain bread is a superfood. Here's why.
The rise of sourdough has been well documented. Everybody loves it, because the taste and texture of naturally leavened bread are way better than yeast-leavened bread.
Conventional industrial bread available in stores and made at home is leavened (filled with pockets of gas) by a single-cell fungus called baker's yeast. Nature has produced thousands of species of yeast. But baker's yeast is almost always a single uniform species called saccharomyces cerevisiae. The same species is called "brewer's yeast" when used to make beer.
The control and isolation of this industrial baker's yeast is an achievement of 19th- and 20th-century science. From the middle ages to the early 19th century, bakers got their yeast from beer brewers. Before that, stretching back at least 5,000 years before the present time, nearly all leavened bread was raised with a process we Americans call "sourdough," but which is also called natural leavening.
Like most transitions from traditional to industrial food processing, the decline of natural leavening and rise of baker's yeast involved faster and more reliable mass production at the expense of health and taste, uniformity at the expense of variety.
Sourdough is a Yukon gold-rush era American word for a broad category of bread leavening that is international and ancient. Sourdough is also the word used to describe the American process for making this kind of bread, and also for the bread itself.
Be warned, however, that there are several types of breads called "sourdough" that use baker's yeast as the main leavening agent. These aren't true sourdough breads, and they don't improve the dough the way a real sourdough process does. Many online recipes, and most sourdough breads for sale in the supermarket, are not real sourdough breads and do not provide the health benefits described in this post. If yeast is listed as an ingredient, the bread does not offer the full benefits of sourdough.
Sourdough bread has become widely available in American bakeries and kitchens in the past 10 years. Naturally leavened traditional breads have been continuously available for centuries in some European countries, including Italy, France, Germany, Russia, Poland and all the Scandinavian countries. The words used to describe this kind of bread are language- and even country-specific. Pumpernickel, pain au levain, and just about every kind of rye bread are traditionally made with a "sourdough" or natural leavening, for example.
Naturally leavened bread is a fermented food like olives, pickles, cheese, tofu, miso, sauerkraut, traditional soy sauce and yoghurt. Like all these foods, the fermentation of bread is something developed over the millennia that improves flavor, texture, shelf-life and above all nutritional quality.
There have been more than 20 species of yeast identified in sourdoughs and more than 40 species of lactic acid bacteria. However, the overwhelming probability is that you'll find in true sourdough starters a species of bacteria called lactobacillus sanfranciscensis (of which there are dozens or hundreds of strains) and possibly a second complimentary bacterium species that is region-specific.
Natural leavening improves the quality of bread in many ways that industrial baker's yeast does not.
The stable co-metabolism between yeasts and lactic acid bacteria creates an environment where other microorganisms cannot survive. This anti-microbial activity is stronger even than refrigeration, improving the safety of bread and making it stay fresher longer and preventing the formation of mold.
Grains are packed with nutrients. But they also contain anti-nutrients, including phytic acid. While phytic acid in small amounts offers health benefits, including anti-cancer action, it also chelates or binds to dietary minerals in the gut in a way that reduces the amount of minerals absorbed into the body.
If you eat a healthy diet with lots of grains and other seeds, it's a good idea to reduce the overall intake of phytic acid. And sourdough-leavened bread is a great (and traditional) place to make that reduction in a major way.
There are several ways to reduce the phytic acid content of grains. Soaking grains can reduce anti-nutrients by about 15%, and sprouting by another 10% or so. But sourdough leavening is by far the most powerful method, reducing phytic acid by up to 75%.
It also increases the solubility of both magnesium and phosphorus, making those minerals much easier to metabolize.
Natural leavening bacteria acts as a "prebiotic" that encourages the growth of bifidobacteria, which is a class of gut bacteria known to reduce allergies and fight cancer.
Natural leavening performs another awesome trick: It takes the phytochemical antioxidants locked inside grains and makes them easily digestible, elevating grains into the same antioxidant-rich class as berries!
Sourdough is sour because the bacteria in a sourdough starter converts the sugars present in flour into lactic acid. This acidity highly compatible with the human digestive system, but fatal to harmful and useless microorganism present in the flour. Lactic acid also activates health enzymes that love acidic environments.
The sourdough fermentation process also affects the proteins in flour. Specifically, the lactic acid bacteria start to hydrolyze (break down into individual amino acids) the proteins gliadin, albumin globulin, which makes them easier to digest and more available.
To summarize, bread grains are somewhat incompatible with human biology. Without fermentation, bread has too much simple sugar, hard-to-digest proteins, unavailable nutrients and too much phytic acid. That's why eating too much yeast-leavened bread leaves you feeling bloated, cramped and lethargic. Industrial bread is inflammatory.
Sourdough leaving and fermentation solves all nutritional problems with bread. It eats the sugar (so you don't have to), it breaks up the protein so your body can use it without stomach problems. It releases the minerals and other nutrients. And it dramatically cuts phytic acid. Well-fermented, whole-grain, ancient-grain sourdough bread is anti-inflammatory, loaded with antioxidants and healthy in many other ways.
That's why on the Spartan Diet we not only recommend bread — only whole-grain, ancient-grain, naturally leavened bread — but we also transform other grain-based foods with the sourdough process.
NOTE: If you’re a Spartan Diet subscriber, I would be happy to send you our 600-year-old starter from Venice region of italy. Just send me request via email to: amira.elgan@gmail.com, and I’ll send it to you right away. - Amira