The history of sourdough is one that dates back thousands of years, a time well before commercial yeasts were discovered. Fermentation is a process steeped in history and one which is common in many civilisations the world over.
The fermentation process that is sourdough bread making has captured the attention of many home bakers in recent times, but it is a process that may be as old as time itself.
The process of sourdough fermentation involves harbouring a colony of wild yeast in a slurry of flour and water. This "sourdough starter" or mother dough as its known forms a symbiotic culture of lactic acid bacteria and wild yeast that produce carbon dioxide responsible for the rising of bread dough.
This was the original form of rising bread used throughout human history, until the discovery of commercial yeast in the mid-19th century.
From the flat breads of ancient Egypt to the modern day magic that is San Francisco Sourdough, the history of sourdough as a leavening agent is an interesting mix, one that continues to evolve, as more and more home bakers jump on this amazing bread production method to make their bread rise.
If you are wanting a brief overview, I've popped a quick guide to the history of sourdough below.
Useful Sourdough Resources (jump to):
- How to Make a Sourdough Starter
- Baking Simple Sourdough Bread - A Beginner's Guide
- Strengthen Your Sourdough Starter for Better Bread
- Where does the yeast in your sourdough starter come from?
Quick Guide To The History Of Sourdough
If you want a "Cliff's Notes" version of the history of sourdough, here's what you need to know in just 60 seconds:
- 3000BC - Earliest sourdough bread in Egypt where "sourdough" was discovered by accident when dough was left out and colonised by wild yeast spores.
- 800BC - Ancient Greeks and Roman Empire adopted sourdough bread processes from Egyptian society. Romans further developed the bread making process and oven building technologies.
- 300 - 700 AD Barbarian period saw the disappearance of bread baking and bread technology.
- 1100s - Profession of "baker" reappeared in France and "Barm" used in Northern Europe as a substitute for sourdough leavening.
- Mid 1800s - Commercial Yeast or baker’s yeast (saccharomyces cerevisiae) discovered by Louis Pasteur (started to decrease the need for the wild yeast of sourdough starters).
- 1849 - Gold miners in California nicknamed "sourdough" because they carried and used sourdough starters to make bread during the Northern California Gold Rush.
- 1849 - Boudin Bakery Established by French Immigrants in the US (birth of San Francisco Sourdough Bread).
- 1906 - Louise Boudin saves famous Boudin sourdough starter from being lost in the Great San Francisco Earthquake.
- 1896 - Sourdough used by miners in the Klondike Gold Rush in Western Canada and Alaska.
- 1980s/1990s - San Francisco Sourdough Bread proves immensely popular and becomes a tourist attraction.
- 2020 - Sourdough has enjoyed a resurgence in popularity after COVID19 pandemic had people searching for hobbies and yeast while locked down in 2020.
Of course the true history of sourdough bread is a lot more complex and interesting than the timeline posted above, but this gives you a quick glance through time and where and when sourdough made an appearance. You can find a very detailed historical explanation here.
Where Did Sourdough Come From?
The sourdough we know today has come from thousands of years of tradition, spread across multiple continents. From the Swiss, the ancient Egyptians to ancient Greece and Rome, Californian Gold Miners in the American West and Klondike Gold Miners in Western Canada and Alaska, sourdough has a rich tapestry of international use.
And while sourdough techniques have certainly progressed over many years, one thing remains the same - this amazing bread has always been made with a combination of flour and water (and more recently salt).
While ancient Egypt is generally heralded as the birthplace of sourdough, evidence of fermented bread has been found in Bern, Switzerland, said to date back 3600BC (around 5000 years ago). There are a few different dates floating around, both the for the discovery of yeasted bread in Switzerland and Egypt.
It's safe to say that the process of fermenting sourdough bread is indeed very old and can be traced back to both Northern European and Ancient Egyptian societies (source) in a time well before ours.
The discovery of wild yeast was most likely accidental
It's more than likely that the discovery of "sourdough" was purely by accident when someone left the dough for the unleavened bread they were making out in the open air and it was colonised by wild yeast. When they baked the dough, the result would have been softer and airer than the stodgy, flat bread they were used to eating. This light loaf of bread became what we know as sourdough bread.
From Ancient Egypt, the process of sourdough bread making spread into the Ancient Greek and Roman Empires, gradually making its way across Europe. All of these civilisations, Egyptians included, were versed in the brewing of beer. In fact it has been documented that the Egyptians later went on to incorporate the foam from their beer brewing into their bread baking.
What Is The Oldest Sourdough Starter Known Today?
The oldest known sourdough starter is said to have originated from clay pots unearthed in Egypt. Seamus Blackley baked a loaf of sourdough bread using yeast harvested from 4500 year old clay pots.
If you want to read more about this 4500 year old sourdough starter, go here.
Now it's pretty cool that this happened and while the Egyptian sourdough starter may have been added to the flour and water used, the actual yeast he baked the bread with after a week of feeding this starter would have also been localised yeast and not exactly the same as the wild yeast spores that the ancient Egyptians baked with (simply because feeding a sourdough starter with different flour and water, combined with the yeast on your hands and in the air changes the composition of the sourdough starter) - you can read more about where wild yeast actually come from here.
How Did Sourdough Bread Find It's Way to The United States?
Sourdough has been made famous in the United States for many years. San Francisco Sourdough is probably the most famous of them all. But how did sourdough even become part of American cuisine? And why?
The history of sourdough bread in the United States can be traced to the Californian Gold Rush where miners, who couldn't always access newly developed baker's yeast, used sourdough starter to make bread in the gold fields.
It's likely that their bread wasn't all that great, but it kept them fed all the same. There are many stories of miners who became sick after eating the sourdough baked on the camp fires of the Californian gold fields.
Sourdough bread became steeped in American culture when the Isidore Boudin, master baker from France, heard about the special flavor held in these sourdough starters and started making sourdough bread with it.
The establishment of the Boudin Bakery made San Francisco Sourdough famous. And in fact it is now a huge tourist draw card for visitors to San Francisco and has provided a goal post for baker's wishing to recreate the famous San Francisco sourdough flavor at home.
The Boudin Bakery still uses the same sourdough starter in their bread today and can be traced back over 150 years to a gold miner's starter. The starter has continued to be refreshed daily with flour and water and continues to harbour Lactobacillus sanfranciscensis - a wild yeast once thought to be unique to San Francisco, but has now been found in other countries around the world.
That being said, Boudin still produces a unique flavored sourdough that people travel thousands of miles around the world to experience.
Why Has Sourdough Experienced A Resurgence?
While the Boudin Bakery made San Francisco Sourdough Bread popular throughout the 1980s and 90s (and still does today), sourdough bread making has made a huge resurgence in the last few years.
There are a few different reasons for this resurgence and together they have come together to make sourdough bread hugely popular, even among home bakers.
Some of the reasons for the recent popularity of sourdough bread include the prevalence of gluten sensitivity and people wanting to be able to enjoy bread with a lower gluten concentration.
Many people are also more educated in nutrition and want to eat more nutrient dense foods. Sourdough bread provides a much more nutrient dense food, despite only consisting of flour, water and salt.
The lower levels of phytic acid contained by sourdough bread mean that it is much more easily digested by our bodies and therefore, the nutrients contained are also more bioavailable.
And perhaps the most recent resurgence of sourdough baking has been due to the COVID19 pandemic which saw many cities locked down throughout 2020. Many people who would normally be at work suddenly found themselves at home, devoid of a hobby.
This boredom, paired with the difficulty of buying commercial yeast at the beginning of the lockdown, created the perfect environment for sourdough to make a comeback. 2020 soon became the "year of the sourdough starter".
However I think what is interesting is that while many home bakers started baking sourdough in 2020, a great number of them have continued to nurture their sourdough starter and bake sourdough bread at home. In fact many of these "COVID Bakers" have gone on to form micro bakeries from their home and continue to bake for their community, despite the lockdowns ending.
Future of Modern Sourdough Bread
Sourdough bread as we know it today is much more refined than it would have been thousands of years ago, or even hundreds of years ago.
Modern home bakers are embracing the weighing of ingredients more and more, bringing more accuracy and consistency to sourdough baking.
Never before have home bakers had access to so many apparatus to help improve their baking, meaning that they can produce a result equivalent (if not better) than a professional bakery.
I believe our love affair with sourdough bread will continue to accelerate into the future as we strive to find a way to ground ourselves in our forever changing, fast paced world.
Frequently Asked Questions
Prior to the discovery of what we now know as commercial baker's yeast in the mid 1800s, all leavened bread was sourdough. That is it, bread dough that was leavened using a colony of wild yeast, now known as a sourdough starter.
Ancient Egyptian society is credited with the discovery of sourdough bread processes, however evidence of yeasted bread was also discovered near Bern in Switzerland said to date back 5000 years.
In more recent times, the United States of America has become famous for producing sourdough bread through the establishment of the Boudin Bakery in San Francisco which uses a starter dating back to the gold rush time in the mid 1800s. From here, it has become a bread steeped in the culture of many throughout the American nation.