Sourdough Starter Science: An Amazing Experiment

The Science of Sourdough Starter and some amazing reasons to “go sourdough.” My little-farm-by-the-river DIL took advantage of pandemic slow time to learn sourdough. Here-in we share some of her discoveries.

The Science of Sourdough Starter

I’m a slow starter on the sourdough bread train.

I’ve enjoyed eating sourdough bread for years. I love the artisan style you get in fine sandwich shops and tea houses.

But I never learned the science behind it.

E.g. I never knew that sourdough starter contains no yeast that is common for baking bread.

Don’t get me wrong. Sourdough starter has yeast, but it is wild yeast, part of the flour mixture itself and from the yeast that float through the air we breathe.

For this reason you start your starter with whole grain flour, so the wild yeast hasn’t been milled out of it.

Another fun bit of trivia says your sourdough will change by address. If you get sourdough from your grandma in Kansas and take it to Arizona, the taste will change because the yeast in desert air does not produce the same taste as yeast in prairie air.

Amazing Reasons To “Go Sourdough”

Why is sourdough better for you than the famous Magic Yeast our mom’s used in their weekly baking?

Because wild yeast is amazing stuff! The flavors are complex and unique, and the sturdy texture makes is more satisfying to chew.

Using yeast bought off the store shelf is the faster and easier way to proof dough. With sourdough starter you wait hours for it to proof, and always discard some starter so you can add more flour and water to keep it fresh and alive. Store bought yeast can produce bread in a couple of hours!

Yet, something about the process of keeping sourdough starter appeals. It creates a sense of home. It takes planning and nurture, yielding to an end result as gratifying as creating art.

What are the Health Benefits of Sourdough?

Most of the world bakes bread with commercial yeast, yet there are some countries that stick to the ancient way of leavening bread.

Would it surprise you if I say one of these places is the Mediterranean?

Sourdough starter relies on wild yeast and lactic acid producing bacteria for leavening, which supports gut health better than bread baked with commercial yeast. (Other foods that contain lactic acid bacteria are yogurt, kefir, pickles, sauerkraut and kimchi.)

Moreover, the lactic acid bacteria in sourdough release antioxidants during fermentation, making the bread easier to digest.  This could be due to sourdough bread’s prebiotic content and probiotic-like properties. Probiotics are beneficial bacteria found in certain foods and supplements.

Read more details about health benefits of sourdough, including insulin absorption, in this post. Or take my son’s word of support for sourdough in his journey to find a sandwich that doesn’t make him sick! He works away from home, and always packs a lunch. His energy levels remain a lot higher through the long, physically challenging days if he’s careful with his diet. Switching to sourdough bread for sandwiches is one of the things that’s helped him.

Ready to make sourdough starter?

How to Make Sourdough Starter

Day 1

Combine 1 cup whole wheat or whole rye flour with 1/2 cup cool water in a 1 quart or larger glass or stainless steel container.  Stir well, making sure there’s no dry flour left. Cover with paper towel or cheese cloth and let the mixture sit at warm room temp (70 degrees) for 24 hours.

Day 2

Not much might happen the first day. There may be a little bubbling. Regardless, on Day 2, discard half the starter, about 1/2 cup, and then add a scant 1 cup of unbleached all-purpose flour and 1/2 cup room temp water to the original starter. Mix well, cover loosely, and let sit for 24 hours.

Day 3

This day you’ll most likely see some activity — bubbling; a fresh, fruity aroma, and some growth. Today you’ll do 2 evenly spaced feedings.  Say, perhaps, at 8:00 in the morning and 8:00 pm. Each time, stir the starter thoroughly, then weigh out a generous 1/2 cup of starter. Discard the remaining starter.  Add a scant 1 cup of all-purpose flour and 1/2 cup water to the saved starter. Mix well, cover, and let rest.

Day 4

Feed twice again, 12 hours apart. Weigh out a scant 1/2 cup of starter, then discard any remaining starter. Add 1 cup all-purpose flour and 1/2 cup water to the saved starter. Mix well, cover, and let rest.

Day 5

Weigh out 1/2 cup starter, and discard any remaining starter. Repeat step 4. By the end of day #5, the starter should have doubled in volume. There should be lots of bubbles, and some little “rivulets” on top that are full of finer bubbles. Also, you should smell a tangy aroma, acidic but not overpowering. If it hasn’t risen much or appears “dead” keep repeating the stir, discard and feed cycle every 12 hours every day until it’s a live, bubbling mass.

Sourdough Starter Science Notes:

When the starter is ready, you’ll give it one last feeding. Discard all but 1/2 cup. Feed as usual, and let the starter rest at room temperature for 6 to 8 hours. It should be active with bubbles breaking the surface.

Remove as much starter as you’ll need for your recipe. If your recipe calls for more than 1 cup of starter, feed it a couple of times without discarding until you have enough for your recipe, plus 1 cup to keep and feed again.

Most of us cringe at discarding all that excess starter. How is that being economical???

Well, don’t worry. There are recipes that make use of discarded starter!

Trust your pioneer fore-women. They wouldn’t waste anything, and you don’t have to either.

Unlike the pioneer women who baked every day, some of us just don’t.

However, you can keep your starter going by storing it in the refrigerator, and stirring, discarding and feeding once a week. If you don’t want to bake, just put it back in the fridge again until you do.

Want to try making Sourdough Starter?

Save to your Pinterest baking board for later reference. And help us spread the word about healthy bread baking!