What’s So Special About Sourdough Bread?
By Fiona Riddle
If you’ve ever taken a bite of freshly baked sourdough, you are familiar with its distinctly tangy flavor and chewy texture. It is the perfect addition to a balanced meal, and can easily be made at home with high quality flours. Furthermore, because it is a fermented food, sourdough also offers many health benefits that make it a more nutritious food than most other bread options. Among these benefits include easier digestion, improved nutrient absorption and steady blood sugar. However, not all sourdough products that you find in stores is truly fermented, and it is important to understand the differences between the two.
Typical bread found at the grocery store is made with commercial yeast, specifically a species of yeast called Saccharomyces cerevisiae. This species is commonly referred to as ‘baker’s yeast,’ or ‘brewer’s yeast’ as it is used in the production of beer as well. Yeast is added to the dough, which feeds off added sugars, producing carbon dioxide. This allows the bread to rise and increase in size as the carbon dioxide expands. Commercial yeast is shelf stable and does not require “feedings” in the way that sourdough does. It also works quickly and facilitates bread making that takes only a couple of hours.
“…essentially a combination of water and flour that ferments with the help of naturally occurring yeasts and bacteria”
In order to make sourdough bread, however, you need a sourdough starter, also known as levain. It is essentially a combination of water and flour that ferments with the help of naturally occurring yeasts and bacteria, which are present all around us. The yeast feeds off the carbohydrates found in flour to produce carbon dioxide, and lactic acid bacteria produce sour lactic acid (which gives sourdough its distinct tangy flavor). Lactic acid also kills unwanted bacteria, preventing the starter from going bad and extending the shelf life of sourdough bread.
“there are no actual probiotics found in cooked sourdough bread as the high temperature of the oven destroys them”
True sourdough has numerous benefits including a lower glycemic index, prebiotic properties, less gluten and better nutrient absorption. A 2021 review noted that while all sourdough starters are unique to the environment and choice of flour, “some lactic acid bacteria (LAB) strains that are part of the sourdough starter are considered as probiotics which have great potential for improving gastrointestinal health”. Even though the process of fermentation gives sourdough many of its added benefits thanks to beneficial microbes, there are no actual probiotics found in cooked sourdough bread as the high temperature of the oven destroys them. Cooked sourdough does, however, contain prebiotic benefits that can “feed” beneficial bacteria in the gut microbiome and confer positive health benefits. The same review suggests that one such prebiotic might be β-glucan, created by the lactic acid bacteria. True sourdough therefore may be easier to digest and better for our digestive health.
“Typical bread contains close to 200,000 ppm (parts per million) of gluten, and sourdough contains closer to 200 ppm”
Lactic acid bacteria also plays a role in reducing the gluten content of sourdough bread. These bacteria release protease enzymes that break down gluten over time. Typical bread contains close to 200,000 ppm (parts per million) of gluten, and sourdough contains closer to 200 ppm, although the actual amount depends on factors such as fermentation time and flours used. This makes sourdough bread a potentially suitable option for those suffering from mild non-celiac gluten sensitivity, however it is not a gluten free food and should be avoided by those diagnosed with celiac disease.
“By lowering the glycemic index, sourdough bread has a smaller impact on blood sugar levels”
Its lower glycemic index stems from the actual structural difference of sourdough bread compared to other common breads. The naturally occurring bacteria alter the starches, changing the structure of the bread molecules, making your body absorb them slower, which lowers the bread’s glycemic index. By lowering the glycemic index, sourdough bread has a smaller impact on blood sugar levels and will not have as dramatic an effect on the release of insulin as eating a piece of white bread would. Balanced blood sugar is essential for minimizing sugar cravings, maintaining balanced energy levels, and keeping our bodies metabolically fit.
“Enzymes produced by lactic acid bacteria destroy acids like phytic acid, which inhibit the absorption of certain nutrients such as folate, potassium, and magnesium.”
The fermentation of all grains, including those used for bread, is a common, ancient practice that makes these foods more easily digested and nutritious. Enzymes produced by lactic acid bacteria destroy acids like phytic acid, which inhibit the absorption of certain nutrients such as folate, potassium, and magnesium. Consequently, we are able to absorb and utilize greater amounts of these naturally occurring vitamins and minerals.
“If you notice any additives on the ingredient label such as yeast or baking powder, this is an indication that the bread is not truly sourdough”
If you’re curious about what to look for when shopping for sourdough, it’s important to know that true sourdough is made with just flour, water, and salt. If you notice any additives on the ingredient label such as yeast or baking powder, this is an indication that the bread is not truly sourdough. And because it is not truly fermented, it will not have the same health benefits.
Another ingredient to be weary of is citric acid. Citric acid is an organic compound naturally occurring in citrus fruit that gives it its distinct tart, sour flavor. Consequently, it is often added to bread in order to mimic the natural tangy flavor of sourdough. Just because a bread tastes sour though, does not mean that it is truly sourdough.
“The benefit of making your own bread is that you can choose exactly which flours you use to alter the nutrient density, taste and texture.”
If you would rather make sourdough at home, it is easy to get started – all you need is some flour, water, and a jar. The benefit of making your own bread is that you can choose exactly which flours and techniques you use to alter the nutrient density, taste, and texture. Plus, making your own sourdough bread is a great way to get closer to your food, and you will be able to eat it when it’s fresh out of the oven!
Fiona Riddle is a Certified Health Coach with a degree in Psychology from UCLA. She is passionate about a holistic approach to health when working with her private coaching clients. She is an avid cook, constantly creating and sharing new recipes on her Instagram (@feelgoodwithfi) to showcase simple clean home cooking. She has helped clients take their health into their own hands and successfully boost their energy and confidence through sustainable lifestyle changes. www.feelgoodwithfi.com