The Back Story on Yeast


A Short History of Yeast and Humanity
by Anna Roth
photo by Jill Lightner

I sped up I-5 north to Seattle, listening to The Grapes of Wrath on tape and talking to my sourdough starter. It was bubbling with life in a Styrofoam cooler on the passenger seat, a bandana tied rakishly around the neck of its Mason jar, displaying an ebullience that mirrored my own. I was 22, a newly minted B.A. jubilantly returning home after four years in the urban trenches of Los Angeles.

To the uninitiated, a sourdough starter sounds like a lousy co-pilot—it’s a soupy mixture of flour and water, about the color and consistency of a melted milkshake. But to see it only for its parts is to miss the beauty of the whole. My starter represented something greater than myself. It was a link with my past and a lifeline to my future. I knew it would adapt to its environment with little effort, seamlessly incorporating the new into the old. That week, on the cusp of the biggest transition of my life, I was willing to cling to anything that might help me do the same.

In the summer of 2005, Seattle, too, was in the process of change—it was a city coming of culinary age. The scene still emphasized honest ingredients and square meals, but a whiff of pretension was in the air. Trends blew in from faraway places like Spain and New York in the form of saffron foam and gastropubs. I despaired of what was happening to the laid-back city I loved, but should have been reminding myself what else was in the wind.

Wild yeast—the soul of a sourdough starter—has been the silent observer of Seattle’s growing pains over the past two centuries. It was there before Henry Yesler built his sawmill; before the Denny party came ashore at Alki. Wild yeast offers us the certainty that the world will change, and the assurance that we can change with it. Thinking about its lifespan—nothing less than the course of human history—is enough to assign microgreens and $15 burgers their proper significance.

Yeast is a living organism that floats in the air, alongside dust and radio waves and Wi-Fi. A starter, made of roughly two parts flour to one part water, is just a home where yeast can feed and reproduce. Yeast can survive indefinitely, provided the temperature doesn’t rise above 140 degrees Fahrenheit, but certain strains have more pedigree than others. Geographic dispersal has led to mutation; on the internet, diehard foodies will swap yeast from Napoleonic France and ancient Egypt with a reverence usually reserved for rare coins.

Yeast’s leavening properties were probably discovered by accident sometime around 1,500 B.C. Until commercial yeast came on the scene in the nineteenth century, bakers had to wait for wild yeast to take up residence in their dough. It could take days. To save time, they’d reserve part of their previous batch, adding flour and water and leaving it in a warm, shady place.

Maintaining a starter requires a certain amount of effort. At room temperature, it needs to be fed flour and water twice a day, or it will start to break down and produce a brownish alcoholic discharge called hooch. For the sake of convenience, modern bread bakers often refrigerate their starters, which slows their growth to the point that they only need to be fed once a week. Looked after properly, a starter can live forever.

Sourdough is unique among breads because it depends on wild yeast—the signature tang comes from fermentation with lactic-acid producing bacteria that cannot occur with commercial yeast alone. It’s an organic, mysterious process that inspires a certain cult-like following among bakers. Sourdough starters are cosseted like children, and shared between friends and through generations. Occasionally they even show up on Craigslist, free to a good home.

Even with the same parentage, no two batches of sourdough stay alike for very long. As starters move in space and time, they take in yeast from the air around them. They become individuals. Ethiopian injera, Russian rye and Scandinavian pumpernickel are all sourdough breads. Like the people it nourishes, each sourdough is defined by its past and its present; it can never escape where it’s been.

Seattle’s image of itself has is tied intrinsically to its cycles of booms and busts. It was nothing but a beautiful and lonely mountain town, until the steamer Portland chugged into Elliott Bay one July day in 1897, laden with 68 men and a ton of Alaskan gold. The resulting Klondike Gold Rush quite literally put Seattle on the map overnight. Savvy city planners marketed the city as the last refueling point before the great frontier—”The Gateway to the Gold Fields”—and tens of thousands of men came running: buying supplies, getting drunk in Pioneer Square saloons, staying aloft on dreams of fame and fortune. They’d come back through town in months or years, transformed into crusty prospectors who became known as Sourdoughs, after the substance that had sustained them in the wilderness.

They didn’t mind the nickname. To maintain a sourdough starter was to ensure they would come back—and sourdough has always been a staple of existence in the West. Settlers carried buckets of it on their wagon trains. Cowboys depended on it in their chuck wagons. Up in the unforgiving Yukon Territories, a Sourdough nurtured his starter like a beloved companion, taking it under the blankets at night and feeding it regularly (it was not unusual for prospectors to travel with eight sacks of flour in tow). When hooch formed, he would drink it. Come morning, his starter would nurture him in return—the smell of sourdough pancakes on a griddle, or a pan of biscuits, warm and tangy from a Dutch oven.

And in pancakes lies the key: The starter is only the raw material, the magician’s hat, the staging ground. A sourdough starter is a tangible reminder of the future’s inevitability, but also of its promise. The starters sold to potential millionaires in 1890s Seattle were the same starters that had witnessed the city burn to the ground in 1889. Yeast in the air today has seen us through the Boeing recession of the 1970s and the roller-coaster ride of the dot-com era. Sourdough contains the wisdom of the ages: Trends will come and go, gastropubs will open and close, cities will prosper and decline, but bread will also rise tomorrow.

Last fall, I moved back to Los Angeles after an impetuous young marriage careened off its tracks. While cleaning out my former apartment, I came across my sourdough starter at the back of the fridge. It had been neglected for months, and a thick, dark layer of hooch rested accusingly on its surface. I lingered for a second, remembering its limitless potential, and mine, on our exuberant drive from California three years before. But then I threw it away. It was beyond resuscitation, and time to move on.

Heritage Starters

If you crave the flavor of a specific regional bread, playing around with heritage starters can get you closer to the original. Most of the websites listed provide specific flavor profiles and precise origin of their individual starters. New England:
Oregon Trail:
Northwest, Europe and Australia:
San Francisco, Africa, Eastern Europe and Saudi Arabia:
Europe, Australia, Canada, Ozarks, New England: Try our recipe to make your own homemade, wild yeast sourdough starter.
Once you’ve got some sourdough starter, fix up some old-school sourdough pancakes.

Anna Roth is a freelance writer and editor. To learn more about her, please visit her website:

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