Sourdough's Big Come Back—Why Is Something So Old, New Again?

Sourdough's Big Come Back—Why Is Something So Old, New Again?

Sourdough's Big Come Back—Why Is Something So Old, New Again?

In celebration of #SourdoughBreadDay this week on April 1st, this post looks back at the history of humankind's cultivation of grain and its use of wild yeast as leavening. Dating back in antiquity, bread production relied on the use of sourdough as a leavening agent for most of human history; the use of baker's yeast as a leavening agent dates back less than 150 years.

The history of humankind's cultivation of grain and the use of wild yeast as leavening is an ancient practice that dates back at least 5000 years. However, no single region can lay claim to discovering that flour and water, will ferment and can be added to dough, making is raise and lighten up into delicious loaves of sourdough bread. And that is because it is a spontaneous event that occurs naturally everywhere on Earth, (well maybe not at the North and South Poles).

But in the USA, wild, natural yeast is synonymous with sourdough and prospecting in California and Alaska. Like them, the pioneers made sourdough a symbol of the "West" too. Each family carried a family-start called a 'sponge' from the old country, which was carefully tended by pioneers as they traveled west in their wagon or handcarts. Many of these starters were handed down from generation to generation brought with them from Europe when they emigrated to America.

However, this kind of bread was not born in America. The oldest form of leavened bread goes back much further than just a century and a half ago.


"Homemade sourdough bread, it seems, became a rather annoying Covid-19 hipster version of the Victory Gardens of World War… only more precious."— Reddit

Still this ancient method has really caught on world-wide during the recent pandemic. Food Business News reported, that "home bakers [they surveyed] indicated their increased attention to baking soothed and relaxed them (46%), provided a sense of accomplishment (42%), filled the increased free time at home (40%) and helped involve and entertain child bakers attending virtual school (27%). Others sought the cost savings versus store-bought bread (25%) or found it hard to find bread on store shelves (18%)." And of all those home bakers, they found, "thirty-one percent of respondents baked a sourdough loaf," during the pandemic

"I'm not saying that a sentient sourdough culture created COVID-19, I'm just suggesting we should look at who has benefited the most from this virus."—Molly Hodgdon

Yeast it seems  "is a happy accident, wrote Vox. "It is all around you, all the time. It’s on the surfaces you touch every day. It’s on the packages you get delivered and on the skin of those you come in contact with. It’s in the air. You can also buy it in the supermarket (sometimes)…"

They pointed out that "bread baking is a thing we do in a crisis, perhaps because bread is one of the very foundations of human civilization, and perhaps because it has been marketed to us as life-giving.
"In the midst of quarantine, we have turned, seemingly collectively, to techniques from the past, like coaxing yeast out of the air, the sort of sufficiently advanced technology that is indistinguishable from magic. We have learned to create something from nothing."

Ancient Discovery of Sourdough

Our story actually begins with the domestication of grass seeds that eventually produced grains like barley, rye and later wheat. We are unsure of when this all started but scientists have been finding evidence of grain cultivation as early as 9,000 BC. Interestingly though, grass seeds as grains are not digestible by humans unless they are ground first to break them down. No one is sure how humans first consumed those grains, but records show about 8000 BC, in Egypt, quern stones were used to crush grains, so they had figured that much out. 

This early version of flour was probably combined with boiling water to make a gruel or paste (or grains may have been toasted, which also makes them digestible). From there, bakers could have produced flatbreads, something like the Indian chapatis or Mexican tortillas made in modern times.

No one knows who first left water and flour out for a week to pick up the local airborne yeasts that then combined with the microorganisms found on wheat to naturally grow the first levain. But Egyptians who were skilled beer brewers were likely among the first to bake leavened bread, as the wild yeasts they brewed beer with were very similar to the ones found in ancient bakeries there. 

Egyptian records show early use of fermentation in brewing beer and making bread. These ancients, like others around the world, discovered that by adding water to ground grains a fermentation process developed over time. This, of course, allowed them to make beer and use the process in "baking leavened bread with use of sourdough, as proved by wall paintings and analyses of desiccated bread loves and beer remains," as reported by Emad Mohamed Ali Karrar, ing July 2o16 in hIA "A Review On: Characteristics and Classification of Sourdough and Its Impact On the Bread Properties, Chemical composition and Fermentation of Sorghum," published in the International Journal of Food Science and Nutrition Technology.

But more recently, Seamus Blackney, a scientist, hardcore amateur, baker and Egyptologist, baked a loaf using a starter he collected from "4,500-year-old Old Kingdom vessels used to bake bread and make beer from the Peabody Essex Museum and Museum of Fine Arts in Boston," as reported Jason Daley for the Smithsonian in August 2019

And on Twitter, Seamus Blackley described his bread as "much sweeter and more rich than the sourdough we are used to." 

From Egypt, baking bread this way became tradition in the Middle East. In their A History of Ancient Israel and Judah, Hayes and Miller explained that the Jewish diet around 700 BC was built on oil, bread, and wine. Nearly every common family sustained life with just these three foods. To leaven their bread, a lump of dough from the previous day's bread was kept for making new loaves the following day.

Also about this time, the first earthen bread ovens were built and wheat worked its way into the fields of Middle Eastern farms. Both of these developments improved bread-making dramatically.

Then in their day, reported the Chicago Tribune, "the Romans sometimes used a leaven made of grape juice and millet to hasten the fermentation of their bread. The juice contained yeast from the skins of the grapes,"  (see Country Home Magazine, The Rise and Fall of Ancient Bread, Chicago Tribune, February 9, 1986)

But "the origins of bread-making are so ancient that everything said about them must be pure speculation," wrote Michael Gaenzle, in April 2014, in the Encyclopedia of Food Microbiology (2nd ed.)  Continuing he wrote, "One of the oldest sourdough breads dates from 3700 BCE and was excavated in Switzerland, but the origin of sourdough fermentation likely relates to the origin of agriculture in the Fertile Crescent several thousand years earlier."

Nonetheless, down into the Middle Ages, sourdough starters remained the usual form of leavening bread until barm, (the foam that forms on beer during fermentation) came into use in Britain. But for the rest of Northern Europe, where most bread was made from rye, sourdough was a better leaving agent. Barm and rye did not work well together. However, as wheat became more common, brewer's yeast came into fashion too.

Yet, the Smithsonian records, "Christopher Columbus was the first person to bring European sourdough to America… He carried with him a crock of bread starter—a fermented product that still takes the place of commercial yeast in artisanal loaves today."

Each sourdough starter varies from one to the next, depending on the Lactobacilli bacteria (LAB) and wild yeast on the baker's hands, and from the air, on the flour milled from whole grain, and in the water used in making it. But among sourdough flavors in the USA, San Francisco Sourdough rules.

San Francisco Sourdough vs Commercial Baker's Yeast

Looking at the San Francisco Sourdough phenomenon,  as the California Gold Rush drew in thousands of people, "they found that the bread they made tasted different—more sour, chewier, tangier—than it had back home … [but] it got its official beginning with the opening of Boudin Bakery in 1849, the second year of the rush," documents Eschner.

Fifty years later, during the "Alaskan Klondike [gold rush], records King Arthur Flour, "miners used fermented dough, hung in a tin above the stove, to make bread, biscuits, and flapjacks." And over time the word "sourdough" itself became synonymous with these Alaskan prospectors and their dough, as both were referred to as "Sourdoughs." And nearly all of these prospectors carried their starters buried in their bags of flour or in tins strapped to their backs too keep them from freezing.

But during this same period, records Country Home Magazine Bread, "Austrian chemists developed a system for mass-producing yeast. The yeast was sown in vats containing fermenting brew. When it rose to the top, the yeast was removed and washed, and some of the water was removed by pressure. It was then formed into ready-to-use cakes.

"Bakers were wary of this new product, called dried yeast or German yeast, because it didn't keep well and it was often bulked out with starch, chalk, and pipeclay. But by 1900, journals were carrying advertisements for yeast, all claiming the purest quality.

"In 1863, an immigrant named Charles Fleischmann went back to Austria to search for a good-quality baker's yeast and returned to America with the yeast cells in a test tube in his vest pocket. In 1868, he began selling compressed yeast wrapped in tin foil.

"With the onset of World War II, the U.S. government sought a dehydrated yeast that could be used to make bread on the battlefield. In 1943, Fleischmann`s company produced the first active dry yeast. After the war, dry yeast was introduced to the retail market and is now the form of yeast most commonly used for home baking."

Sourdough's Comeback

But these days, the idea of leavening bread with sourdough is making a big come back, especially during the Covid-19 Pandemic of the last few years

"Why?" you might ask, especially with the convenience of instant packaged yeast. Frankly, early on in the pandemic it was hard to find. But the real answer has two-parts including flavor and nutrition.

The dense crusty artisan loaves we know as sourdough develop deep unique flavors that are released from the long-fermentation process it takes to make this bread rise. And as many hobby bakers tried it for the first time these last few years, they found the flavor compelling them back to bake sourdough time and again.

In addition, most bakeries using sourdough starter will begin with freshly stone-ground flours like whole wheat, rye, einkorn, spelt, and others, that are rich in vitamins and minerals, especially when just milled, which home bakers can do with their own mills too,

Commercial bread is rushed by using instant yeast and only takes 2–3 hours. A loaf of sourdough bread will be left to rise 12–48 hours. This gives the bread its trademark taste and name.

Commercial bakeries use refined flour stripped of many of the vitamins, minerals, and fiber found in unrefined flour. To make up for this loss many artificial ingredients are added to fortify their bread.

The long-fermentation process releases nutrients lost with quick rising yeasts. That same long process that makes the bread rise, breaks down some of the gluten, making it even more agreeable for those who are gluten intolerant. It also delivers more fiber for your digestive tract slowing down the glycemic response to the carbohydrates found in grain.

Sourdough served mankind for millennia. Maybe it's time for it to come back into your diet.

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.