Inside Our Food

Sourdough | History Rises Again

Today sourdough is considered an artisanal bread, but 160 years ago nearly all bread was sourdough. What changed?

Sourdough – History rises again

No one knows who made the world’s first raised bread. But it’s likely to have happened after humans invented agriculture. Settling in one place, experimenting with mixtures of grain, someone probably noticed a mixture of crushed grains and water forming bubbles after a few days – the tell-tale sign of fermentation.

From Fermentation to Sourdough

Fermentation occurs when microbes (like bacteria and yeast) digest substances, producing gas and other products. Milled flour naturally contains strains of Lactobacillus bacteria and wild yeast from the environment, and these microbes can digest starches and sugars in the flour. Ancient civilisations would have found out that this frothy mixture, when baked, produces a softer and fluffier alternative to early flatbreads. This began the trend of ‘leavening’ bread, making bread rise by incorporating substances (like microbes) to put gas bubbles in the mixture.

Sharing the Dough

Does this process sound familiar? It’s actually how sourdough is traditionally made! So ancient leavened bread was just sourdough. Sourdough was eaten by the ancient Egyptians, taken to America by French bakers during the Gold Rush, and nurtured in bakeries across Europe.1

So what changed? Eventually bakers figured out that it was yeast that did the bulk of the leavening–adding yeast to a dough mixture gave fast and reliable results. In 1857, French microbiologist Louis Pasteur identified yeast under the microscope, which led to the creation of commercial baker’s yeast. Bread production was transformed, and sourdough was no longer the only option.2

Fun fact: For a while, bakers used brewer’s yeast which gave the bread a bitter flavour.

What’s in a sourdough?

But Lactobacillus and yeast don’t just change the texture of bread, they change its chemistry. Raw sourdough is a living thing, a changing blend of microbes, and it’s the natural balance between the yeast and bacteria which makes sourdough so special.

As the microbes grow and live and ferment, the Lactobacillus produce lactic acid and the yeast produce alcohol, giving the bread a tangy and acidic flavour. The acid in the dough also keeps out other types of fungus and bacteria, so the eventual bread has a longer shelf life. The microbes also digest gluten, meaning that real sourdough should either be low in gluten or gluten-free—so people with gluten-intolerance and celiac disease to might be able to eat sourdough.3

Fun fact: The lower amount of sugars means sourdough also has a lower glycaemic index than many types of other bread.

You might be eating 100-year-old sourdough

In the past, bakers found they could save some leavened sourdough to add to new mixtures, which would convert them into more sourdough. With careful feeding of flour and water, these so-called ‘starter doughs’ can be kept alive indefinitely. In fact, there are starter doughs in modern bakeries that may be hundreds of years old.

Across the world, jars of starter doughs have been treated like family heirlooms, passed down through generations. Starter doughs were carried by frontier settlers and Gold Rush prospectors, snuggled at night to keep them warm and alive.

Fun fact: Each starter dough really is unique, a potted history of local flour and microbes from the environment - including the Lactobacillus found naturally on the baker’s hands.4

Traditional sourdough continues to be made and sold today in bakeries and artisanal markets. There’s a sourdough library in Belgium which aims to collect and catalogue starter doughs from around the world.5 In Sweden, a sourdough hotel will maintain your starter for you while you vacation.6 You could make your own starter using just flour, salt and water, or purchase a regional starter dough over the web. And you might decide the starter’s history doesn’t really matter - scientists have found the same distinct strains of Lactobacillus in San Francisco starter doughs as in bakeries across Europe.7

But is it real sourdough?

But while some bakers are fiercely proud of their traditional sourdough and treasured starter doughs, there is no legal definition of sourdough. It’s really the Lactobacillus which is key to creating sourdough, yet there is no official legislation stating a sourdough loaf has to contain any Lactobacillus.8

Though 30–50 % of European breads are produced using sourdough, industrially-produced sourdough uses dried starters rather than a spoon of sticky dough from a treasured pot.  Other ‘sourdough mimics’ are likely leavened using yeast, and artificially soured with additives. And  sourdough mimics may not have the time or microbes needed to break down the gluten in grains. Which means, if you are gluten-intolerant or avoiding high GI-foods, there is even more reason to care whether your sourdough is authentic or not.

Slow to produce, nurtured like a pet, is sourdough worth making the traditional way? Let us know what you think in the comments below!

Related articles

Most viewed

Inside Our Food

How is Sugar Made?

Madhura Rao

What is sugar? If you like chemistry, you might say ‘an organic chemical’. If you enjoy…

Inside Our Food

Cheese—to pasteurise or not to pasteurise?

Meghan Horvath,Luke Cridland

Since its discovery in the nineteenth century, the process of pasteurisation has helped preserve…

The Future

AI and the Future of Flavour

Annabel Slater

Ever thought to pair oysters and kiwi? How about caviar on your white chocolate? These pairings…

Inside Our Food

The Ethics of Foie Gras

Claudia Lee

A symbol of ‘haute cuisine’, the story of foie gras began millennia ago in Ancient…

Inside Our Food

Are “Natural Foods” Better For You? | Opinion

Lottie Bingham

A quick scan of the supermarket shelves will reveal a wide array of different foods labelled…

Inside Our Food

How is Salt Made?

Lottie Bingham

Salt is used across industries and cultures, and has held an important place in society for over…

Earth First

Quinoa | A Climate Proof Food

Merel Deelder

Due to the effects of climate change, producing enough food for our growing world population is…

Earth First

Trace Your Food Back to its Source

Marie Lödige

Do you ever wonder where your food comes from or where it’s been on its journey to your plate?…

Inside Our Food

Sourdough | History Rises Again

Annabel Slater

Today sourdough is considered an artisanal bread, but 160 years ago nearly all bread was sourdough.…

Earth First

Sustainable Protein Powders | Whey vs Plant-Based Protein Supplements

Aran Shaunak

Whether for health reasons or in an effort to improve athletic performance, many people turn to…

Inside Our Food

Is Sugar The New Tobacco?

Silvia Lazzaris

Understanding the impacts of sugar on our health is not an easy task. Food science is complicated…

Inside Our Food

What Are Rice Noodles and How Are They Made?

Samanta Oon

Rice is one of the most important grains in Asian cuisine. So important that in several Asian…

Keep updated with the latest news about your food with our newsletter

Follow Us