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Sourdough history

The history of sourdough.

Long before yeast came in packets, bakers raised bread with leavens they made themselves.1 A bit of sour dough saved from yesterday, or the foam from brewing beer.1, 2 This is that story, from burnt crumbs in a desert fireplace to the jars people feed today.

The same story as a 9:55 video, every source numbered on screen. Nothing loads from YouTube until you press play (privacy). In the video, the narration and the music are made with AI, and so are some illustrations and the map drawings, labelled on screen. The cover photo is the loaf from a tomb at Thebes in chapter 2 (The Met, CC0), cropped.

Chapter 1

How old is bread?

Our story starts in north-east Jordan, at a hunter-gatherer camp called Shubayqa 1, in the Black Desert.3 In an old stone fireplace there, researchers found burnt crumbs of a bread-like food, about 14,400 years old.3 According to the researchers, that’s at least 4,000 years before farming began in the region.3

Black Desert, Jordan
Black Desert, Jordan Photo: Joe Roe, CC BY-SA 4.0 · Source

The flour probably came from wild cereals, such as wild einkorn, and some crumbs seem to contain ground tubers of a marsh plant, club-rush.3

Wild einkorn
Wild einkorn Tracey Slotta, USDA-NRCS, public domain · Source
Club-rush
Club-rush Photo: Krzysztof Ziarnek, CC BY-SA 4.0 · Source

Their air pockets are tiny, so it was probably flat: more like a flatbread than a risen loaf.3 A 2024 find from Türkiye was called the world’s oldest bread. At about 8,600 years, it’s younger. The Jordan crumbs are still the oldest we know of.3, 4

Chapter 2

Did Egypt invent sourdough?

First, what is it? A sourdough starter is just flour and water, taken over by wild yeasts and bacteria.5 Broadly, the yeasts make the gas that puffs up the dough. The bacteria make acids, and that’s the sour.5 According to sourdough microbiologists, bacteria usually outnumber the yeasts ten to a hundred times.6 Egypt’s dry desert kept real loaves. One, now at The Met, is about 3,500 years old, from a tomb at Thebes.7

A loaf from a tomb at Thebes, about 1491–1473 BCE
A loaf from a tomb at Thebes, about 1491–1473 BCE The Met, CC0 · Source

About 4,000 years ago, an Egyptian named Meketre was buried with a tiny model bakery and brewery.8

Model bakery and brewery, tomb of Meketre
Model bakery and brewery, tomb of Meketre The Met, CC0 · Source

In a 1996 study, archaeologist Delwen Samuel examined ancient Egyptian bread under the microscope, and found signs that some was made with yeast.9

Bakers and brewers from Meketre’s model
Bakers and brewers from Meketre’s model The Met, CC0 · Source

So did Egypt invent sourdough? Honestly, nobody knows. The best-preserved evidence isn’t the same as being first.3, 10

Chapter 3

Is Europe’s oldest sourdough Swiss?

In Switzerland, Twann is a lakeside village on Lake Biel, where Stone Age farmers lived about 5,500 years ago.11 According to Switzerland’s UNESCO pile-dwellings group, a small charred bread from Twann, from about 3560 BC, is Europe’s oldest preserved sourdough bread.11

Twann on Lake Biel, 2017
Twann on Lake Biel, 2017 Photo: JoachimKohler-HB, CC BY-SA 4.0 · Source

But there’s a catch. According to a 2017 study, the pioneer behind these early Swiss bread identifications never published how he made them.10 When scientists examined two similar Stone Age breads from Zürich with modern methods, both turned out flat and unleavened.10

The Zürich breads
The Zürich breads Heiss et al. 2017, PLOS ONE, image: ÖAI-ÖAW, VIAS / A. G. Heiss, CC BY 4.0 · Source

How can they tell? They measure the air pockets. Risen bread has big pores. Flatbread has only tiny ones.10, 3 So, Europe’s oldest sourdough? Maybe. As far as we could find, it hasn’t been re-tested with modern methods.11, 10

Chapter 4

Did the Romans bake sourdough?

Nearly two thousand years ago, the Roman writer Pliny the Elder said that most often, people simply kept back a little of yesterday’s dough.1, 2

Wall painting from Herculaneum, Naples museum
Wall painting from Herculaneum, Naples museum Photo: Carlo Raso, public domain · Source

He even wrote that whatever makes dough rise is sour by nature.1 In Gaul and Spain, he says, people raised bread with the foam from a grain drink, a kind of beer, and got lighter loaves. That’s a yeast leaven, not sourdough.1, 2 When Vesuvius erupted in 79 CE, one Pompeii bakery’s oven held 81 loaves, according to the excavators.12 At nearby Herculaneum, one charred loaf is stamped with a name: Celer, the slave of Quintus Granius Verus.13 A fresco from Pompeii is often called a bread sale. But some scholars think it shows bread being handed out for free.14, 15

Fresco from Pompeii, Naples museum (inv. 9071)
Fresco from Pompeii, Naples museum (inv. 9071) Photo: Marie-Lan Nguyen, public domain · Source

Chapter 5

Why is rye bread sour?

Rye is thought to have started out as a weed in wheat fields. From the Middle Ages on, it became one of the most important crops in much of Europe.16, 17

Ivan Shishkin, Rye, 1878
Ivan Shishkin, Rye, 1878 Tretyakov Gallery, public domain · Source

But rye dough can’t build the stretchy gluten web that holds wheat bread up, even though rye still contains gluten.18

A harvested rye field
A harvested rye field Photo: “Harvested Rye field on Gallows Law” by M J Richardson, CC BY-SA 2.0 · Source

And rye flour is full of starch-breaking enzymes, which can leave the bread sticky inside.18 According to food scientists, souring the dough partly holds those enzymes back. That’s why rye bakers traditionally used sourdough.18 In Estonia, Latvia and Lithuania, sour rye bread still has a special place, and it’s still very popular.19

Chapter 6

Who first saw yeast?

On the 14th of June 1680, Antoni van Leeuwenhoek, a tradesman and city official in Delft, wrote to London’s Royal Society about beer yeast.20

A copy of a Leeuwenhoek microscope
A copy of a Leeuwenhoek microscope Wellcome Collection, CC BY 4.0 · Source

Under his microscope, he saw tiny balls he called globules.20

Leeuwenhoek’s drawings of yeast, 1680 (printed 1694)
Leeuwenhoek’s drawings of yeast, 1680 (printed 1694) public domain · Source

According to the scientists who edited his letters, it’s the first known description of yeast under a microscope. And he had no idea these little balls were alive.20

Jan Verkolje, Antoni van Leeuwenhoek, about 1680–86
Jan Verkolje, Antoni van Leeuwenhoek, about 1680–86 Rijksmuseum, CC0 · Source

Only in the 1850s and 1860s, according to yeast researcher James Barnett, was yeast established as the living cause of fermentation.21 In 1857, Louis Pasteur argued that the souring, lactic-acid fermentation was caused by something tiny and alive.22, 23

Albert Edelfelt, Louis Pasteur, 1885
Albert Edelfelt, Louis Pasteur, 1885 public domain · Source

Chapter 7

When did yeast go on sale?

By 1872, a firm near Cincinnati, Fleischmann and Company, had registered a trademark for its Compressed Yeast: fresh yeast pressed into a cake.24

Fleischmann & Co. trademark, 1872
Fleischmann & Co. trademark, 1872 Library of Congress, no known restrictions · Source

At America’s 1876 Centennial fair in Philadelphia, the company ran a working Vienna Bakery, to show off bread made with its yeast, according to its own trade card.25, 26

“Vienna Model Bakery” trademark, 1877
“Vienna Model Bakery” trademark, 1877 Library of Congress, no known restrictions · Source

Pressed yeast wasn’t an American invention. According to Europe’s industrial-heritage route, a yeast factory was founded in Delft in 1869, by a man who’d learned yeast-making in Austria.27 And the yeast packet? According to a US Army report, active dry yeast, the kind that needs no fridge, was developed commercially during the Second World War.28 But sourdough never went away.29

Chapter 8

Why call a prospector a sourdough?

In August 1896, Skookum Jim and his family found gold near the Klondike River, in Canada’s Yukon.30 About a year later, the news hit the outside world. Around a hundred thousand people headed north.30

Klondikers at the Scales, Chilkoot Pass, 1898
Klondikers at the Scales, Chilkoot Pass, 1898 Eric A. Hegg, public domain · Source

From the Alaska ports of Skagway and Dyea, tens of thousands climbed the mountain passes, each with a year’s worth of gear and supplies.30, 31

The last climb to the summit of Chilkoot Pass, 1898
The last climb to the summit of Chilkoot Pass, 1898 Eric A. Hegg, public domain · Source

In Alaska and the Yukon, sourdough became a nickname for an old-timer. Merriam-Webster says it came from the sourdough bread of the prospectors’ camps.32 In 1907, Robert W. Service published Songs of a Sourdough. One copy from that same year already says seventh edition.33

Robert W. Service, Songs of a Sourdough, 1907
Robert W. Service, Songs of a Sourdough, 1907 Internet Archive, public domain in the US and Canada · Source

Chapter 9

Is San Francisco sourdough special?

One San Francisco bakery, Boudin, says it opened in 1849, the year Gold Rush crowds poured into the city.34

San Francisco, 1849
San Francisco, 1849 Library of Congress, no known restrictions · Source

In 1971, food scientists Leo Kline and T. F. Sugihara published a close look at the city’s sourdough French bread, which they called a hundred-year-old process.29 They grew its sour-making bacteria, apparently for the first time, and named them after the city.29, 35 Today it’s called Fructilactobacillus sanfranciscensis. Fructi, because it likes fruit sugar.36, 37 But according to a 2024 study, it turns up in starters all over the world. It’s named for the city where it was first described, not the only place it lives.38, 5

Chapter 10

Who made the big round loaf famous?

In 1932, a baker named Pierre Poilâne opened a small bakery on the rue du Cherche-Midi in Paris.39, 40 According to France Today magazine, his big round loaves weren’t exactly fashionable, and after the war, many people preferred white baguettes.41 He kept baking them anyway. The bakery says its bread is still raised with a sourdough leaven, and baked in wood-fired ovens.40, 42 His son, Lionel, made that old-fashioned round loaf famous far beyond Paris.39, 43

Chapter 11

What happened to sourdough in 2020?

In one week of March 2020, as lockdowns began, US sales of baking yeast jumped to about seven times the level of a year earlier, according to Nielsen figures published by NPR.44 That year, sourdough bread came third on Google’s list of trending recipe searches worldwide.45 Worldwide, Google search interest in sourdough jumped about six-fold between February and April 2020.46 Interest fell back, then climbed again. In early 2026, it hit its highest point yet.46

Chapter 12

Does your city shape your starter?

In 2021, scientists studied 500 home starters, most of them from the United States.5

Where the 500 starters came from
Where the 500 starters came from Landis et al. 2021, eLife, Fig. 1B (cropped), CC BY 4.0 · Source

Where the baker lived made little difference to which microbes were in the jar, the authors found, even for San Francisco sourdough, though finer local differences might still exist.5 A long-overlooked group, vinegar-making bacteria, explained much of the difference in how fast starters rose and how they smelled.5 And a separate study found that bakers using the very same flour and recipe still ended up with surprisingly different starters.47 So, about 14,400 years after those crumbs in Jordan, people feed jars of flour and water, and are still learning what lives inside.3

Sources

Numbered as in the video and its description. Each line above cites the ones it comes from.

  1. Pliny the Elder, Natural History 18 (trans. Bostock & Riley, 1855), PerseusPliny the Elder (trans. John Bostock and H. T. Riley). The Natural History, Book 18, ch. 12 ('Wheat', Latin 18.68) and ch. 26 ('The various kinds of leaven', Latin 18.102-104). Taylor and Francis, London, 1855; Perseus Digital Library, Tufts University.
  2. Pliny the Elder, Naturalis Historia 18 (Latin, ed. Mayhoff, 1906), PerseusPliny the Elder (ed. Karl Mayhoff). Naturalis Historia, Book 18 (Latin text). Teubner, 1906; Perseus Digital Library, Tufts University.
  3. Arranz-Otaegui et al., bread 14,400 years ago in Jordan, PNAS 2018Arranz-Otaegui A, Gonzalez Carretero L, Ramsey MN, Fuller DQ, Richter T. Archaeobotanical evidence reveals the origins of bread 14,400 years ago in northeastern Jordan. PNAS 115(31):7925-7930, 2018.
  4. Sci.News, 8,600-year-old bread found in Türkiye, 2024Prostak S. 8,600-Year-Old Bread Found in Turkiye. Sci.News, 15 April 2024.
  5. Landis et al., sourdough starter microbiomes, eLife 2021Landis EA, Oliverio AM, McKenney EA, et al. The diversity and function of sourdough starter microbiomes. eLife 10:e61644, 2021.
  6. Comasio et al., sourdoughs from different origins, Frontiers in Microbiology 2020Comasio A, Verce M, Van Kerrebroeck S, De Vuyst L. Diverse Microbial Composition of Sourdoughs From Different Origins. Frontiers in Microbiology 11:1212, 2020.
  7. The Met, loaf from the tomb of Hatnefer and RamoseThe Metropolitan Museum of Art. Loaf of Bread, ca. 1491-1473 BCE, from the tomb of Hatnefer and Ramose (accession 36.3.73). Collection record, accessed 2026.
  8. The Met, model bakery and brewery from the tomb of MeketreThe Metropolitan Museum of Art. Model Bakery and Brewery from the Tomb of Meketre, ca. 1981-1975 B.C. (accession 20.3.12). Collection record, accessed 2026.
  9. Samuel, ancient Egyptian baking and brewing, Science 1996Samuel D. Investigation of Ancient Egyptian Baking and Brewing Methods by Correlative Microscopy. Science 273(5274):488-490, 1996.
  10. Heiss et al., Neolithic bread-like finds from Zürich, PLOS ONE 2017Heiss AG, Antolin F, Bleicher N, et al. State of the (t)art. Analytical approaches in the investigation of components and production traits of archaeological bread-like objects, applied to two finds from the Neolithic lakeshore settlement Parkhaus Opera (Zurich, Switzerland). PLOS ONE 12(8):e0182401, 2017.
  11. UNESCO Palafittes, Twann site pageSwiss Coordination Group UNESCO Palafittes. Twann, Bahnhof (CH-BE-07), site page. Palafittes.org, accessed 2026.
  12. Pompeii in Pictures, Bakery of ModestusDunn J, Dunn B. Pompeii VII.1.36, Bakery of Modestus (quoting Della Corte 1965 pp. 189-90; Scafati 1900 p. 62; Pappalardo 2001 p. 76). Pompeii in Pictures, accessed 2026.
  13. Pompeii in Pictures, Herculaneum, Casa dei CerviDunn J, Dunn B. Herculaneum Insula IV.21, Casa dei Cervi, p. 3 (quoting Pagano & Prisciandaro 2006 p. 205 and Wallace-Hadrill 2011 pp. 242-244; CIL X 8058,18). Pompeii in Pictures, accessed 2026.
  14. Pompeii in Pictures, Casa del PanettiereDunn J, Dunn B. Pompeii VII.3.30, Casa del Panettiere (quoting Della Corte 1965 p. 147; Fiorelli and De Petra). Pompeii in Pictures, accessed 2026.
  15. Tuck, a Pompeian painting of a bread distribution, J. Roman Archaeology 2023Tuck SL. Baked bread to the people: a Pompeian painting of a bread distribution. Journal of Roman Archaeology 36(2):519-531, 2023.
  16. Filatova et al., rye cultivation in Germany, Agronomy 2021Filatova S, Claassen B, Torres GG, Krause-Kyora B, Stukenbrock EH, Kirleis W. Toward an Investigation of Diversity and Cultivation of Rye (Secale cereale ssp. cereale L.) in Germany: Methodological Insights and First Results from Early Modern Plant Material. Agronomy 11(12):2451, 2021.
  17. Behre, the history of rye cultivation in Europe, 1992Behre K-E. The history of rye cultivation in Europe. Vegetation History and Archaeobotany 1:141-156, 1992.
  18. Clarke & Arendt, sourdough technology, Adv. Food Nutr. Res. 2005Clarke CI, Arendt EK. A Review of the Application of Sourdough Technology to Wheat Breads. Advances in Food and Nutrition Research 49:137-161, 2005.
  19. Sarand et al., traditional breads of the Baltic countries, Springer 2023Sarand I, Traksmaa A, Klava D, et al. Traditional Breads from the Baltic Countries (Estonia, Latvia, Lithuania). In: Traditional European Breads, pp. 41-59. Springer, 2023.
  20. Collected Letters of Antoni van Leeuwenhoek, letter of 14 June 1680, DBNLCommittee of Dutch Scientists (eds). Alle de brieven van Antoni van Leeuwenhoek / The Collected Letters of Antoni van Leeuwenhoek, vol. 3 (1679-1683), Letter 62 [32] of 14 June 1680 to Thomas Gale. Swets & Zeitlinger, 1948; digital edition DBNL.
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  31. National Park Service, a ton of goodsU.S. National Park Service, Klondike Gold Rush National Historical Park. A Ton of Goods. nps.gov, accessed 2026.
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  36. Zheng et al., a taxonomic note on Lactobacillus, IJSEM 2020Zheng J, Wittouck S, Salvetti E, et al. A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae. International Journal of Systematic and Evolutionary Microbiology 70:2782-2858, 2020.
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  41. France Today, Poilâne, a tale of loaves and pain, 2013France Today Editors. Poilane, a tale of loaves and pain. France Today, 16 April 2013.
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  47. Reese et al., ingredients and bakers in sourdough starters, mSphere 2020Reese AT, Madden AA, Joossens M, Lacaze G, Dunn RR. Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread. mSphere 5(1):e00950-19, 2020.

Pictures are shown whole and resized, except the video’s cover photo and the map of the 500 starters, which are cropped. Each one’s licence and source are with it.

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