The Magic of Sourdough, Part I: Ancestral Biotech with Nutrition Benefits

Say hello to my doughy little friend.

It’s a bubbling, fermenting colony of bacteria and fungi that lives in my fridge, but it’s nothing to get squeamish about… it’s just sourdough! I started my first starter about 3 months ago, and I’ve been experimenting with this ancient form of baking biotech just about every week since then. It’s been a fun learning experience, and now I feel like I’ve gotten enough of a handle on it that I can share my dietitian/baker perspective. This post is the first installment of a 3-part series covering the ins and outs of the process, along with the reasons why you might be motivated to start up a habit too!

What is Sourdough?

To give a satisfactory answer to this question, let me break it down into two parts:

The History Lesson: If you peer far enough into the past, you’ll find a time when all breads were sourdough breads. At the dawn of agriculture, humans began eating their newly cultivated grains, ground and mixed with water as porridge and flatbread. When these simple batters were left out long enough, they created a moist & cozy home for the local wild yeast and bacteria. That’s when our neolithic ancestors discovered the magical leavening and preserving qualities of sourdough.

The Science Lesson: The sourdough culture is a symbiotic community of microorganisms that naturally grow on the surfaces of grains and in the air around us. These microbial friends include wild yeast (whose fermentation of starches/sugars yields carbon dioxide gas, which creates the air bubbles that leaven bread) and lactobacillus bacteria (whose fermentation yields lactic acid, which keeps the medium acidic enough to resist spoilage, and which also contributes to sourdough’s signature flavor).

Sourdough is Healthy?

If you only think of sourdough as a tangy flavor in specialty breads, you may be surprised to learn about all the attention it’s been getting lately for its nutrition benefits. Research has been revealing some fascinating facts about sourdough, and it’s all due to the probiotic cultures living in this fermented food.

  • Increased mineral bioavailability. Whole grains are full of essential minerals like zinc, magnesium and iron – that’s why dietitians are always on your case to eat more of them! But grains also contain compounds called phytates that bind to these minerals and inhibit their absorption in the gut. The lactic acid created by the bacteria in sourdough breaks down phytates, and consequently increases your ability to absorb the minerals in your bread.
  • Lower glycemic index. The lactic acid in sourdough alters the starch/protein microstructure that forms during baking. The resulting bread has starch that our bodies digest more slowly. Slower breakdown of starch means a less dramatic glucose response, preventing undesirable spikes in insulin. (If you want to really dig into the science, this paper is fascinating.)
  • “Probiotic” benefits. Although our microbial companions are not able to survive their trip through the oven, their byproducts hang in there, providing a variety of the benefits associated with fermented foods. Before they check out, the good bacteria are nice enough to leave us a selection of antioxidant, cancer-fighting and immune-boosting compounds.
  • Elimination of gluten. Enzymes from both the wild yeast and lactobacillus bacteria work together to degrade wheat flour’s gluten proteins into smaller peptides. The microorganisms are so good at this, that researchers have measured certain sourdough breads as having gluten concentrations of just 12 PPM… that’s legally gluten-free! This is good news if you have trouble tolerating gluten (and tolerating the taste of gluten-free breads).

Is your interest piqued? Don’t forget to tune in next week, when I’ll be back to talk about getting your starter started!

NEXT: Sourdough, Part II: The How and WHY of Getting Your Starter Started

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