Sourdough bread, yogurt, sauerkraut, kimchi, and kombucha might seem like completely different foods at first glance. However, they all have one thing in common: their production is based on fermentation—a technique that humans used long before they knew that microorganisms were involved.
Today, fermentation is experiencing a new boom. Sourdough is being started from scratch, kimchi is being pickled at home, and kombucha is available in numerous varieties. The technique is by no means new, however. Archaeological findings show that humans have been intentionally producing fermented foods and beverages for thousands of years. Some evidence of grain fermentation even dates back more than 10,000 years.
But how was fermentation discovered? Why was it so important for early cultures? And how did it give rise to foods like yogurt, sourdough, or kimchi that we still know today?
What is fermentation, actually?
During fermentation, microorganisms such as bacteria, yeasts, or molds transform components of a food. This process creates new substances that can influence factors such as taste, smell, texture, and shelf life.
A scientific definition frequently used today describes fermented foods as foods produced through desired microbial growth and enzymatic conversions of food components.
That sounds technical—but we encounter this process in our daily lives all the time.
Milk becomes yogurt through specific bacteria. Flour and water turn into sourdough with the help of yeasts and lactic acid bacteria. During lactic acid fermentation, vegetables develop the typical taste of sauerkraut or kimchi.
Fermentation is therefore less of a single process and more of an umbrella term for various microbial processes.
How did food fermentation originate?
It is impossible to say exactly who invented fermentation. It was likely discovered independently in different places.
This is quite understandable: microorganisms occur naturally on plants, grains, fruits, and in our environment. If food is stored under suitable conditions, microbial processes can begin even without intentionally added starter cultures.
Early humans did not need to know about yeast cells or lactic acid bacteria to achieve this. They could observe that dough left to sit would rise, milk would become sour and thick, or pickled vegetables would taste different after some time.
The key, subsequently, was experience: certain conditions consistently led to a desired result. This knowledge could be passed on.
Thus, fermentation techniques emerged gradually and were refined over generations.
Fermentation long before refrigerators and tin cans
Today, we can freeze, pasteurize, or transport food in refrigerated containers. For the majority of human history, however, these options were not available.
Fermentation was therefore particularly valuable.
By altering a food item, new aromas could be created, raw materials could be utilized differently, and certain products could be preserved for longer. Fermentation was thus simultaneously a processing technique, a craft, and part of regional food culture.
Archaeological evidence shows, for example, that grains might have been used to produce fermented beverages as early as 13,000 years ago. Fermented products such as bread and beer are also known from ancient Egypt.
Furthermore, fermentation was by no means limited to Europe or the Mediterranean region. Entirely unique processes developed on different continents, depending on which food items were locally available.
Sourdough: Fermentation from flour and water
Sourdough is likely one of the most famous examples of traditional fermentation.
The foundation could hardly be simpler: flour and water are mixed together and left to sit for an extended period. Under suitable conditions, a community of yeasts and lactic acid bacteria develops within it.
These microorganisms transform the dough. Yeasts produce carbon dioxide, among other things, and help the dough to rise. Lactic acid bacteria produce acids and thereby shape the aroma and properties of the sourdough.
Fermented doughs were already being used in ancient Egypt. Historical and archaeological sources show that humans used yeasts for bread production long before the microorganisms themselves could be scientifically described.
The principle has hardly changed to this day: a portion of an active sourdough starter is kept and maintained with new flour and water.
In this way, a fermentation culture can theoretically be preserved for many years.
Yogurt: When milk suddenly became usable for longer
The fermentation of milk also has a long tradition.
Milk provides excellent growth conditions for microorganisms. Certain lactic acid bacteria partially convert the milk sugar it contains into lactic acid. This lowers the pH value, the milk becomes more acidic, and its structure changes.
This exact principle is behind yogurt and numerous other fermented milk products.
Historically, milk fermentation was likely particularly important for cultures that kept animals and transported or stored milk. Depending on the region, very different products emerged from this—from yogurt and kefir to various types of cheese.
What originally stemmed from observation and experience is now carried out in a controlled manner: modern yogurt production utilizes precisely selected bacterial cultures.
Kimchi: Fermentation as part of Korean food culture
A particularly well-known example of fermented vegetables is kimchi.
"Kimchi" does not refer to a single recipe. There is a multitude of different varieties that can be made from ingredients such as napa cabbage, radish, and other vegetables.
During fermentation, lactic acid bacteria in particular multiply. They transform the sugar components of the vegetables and, among other things, provide the characteristic sour taste.
Historically, the production of fermented vegetable products had a practical advantage: seasonal harvests could be processed and utilized for longer.
Over time, however, it developed into much more than a method of preservation. Kimchi became a staple of Korean cuisine and demonstrates particularly well how closely fermentation and food culture can be intertwined.
Kombucha: Fermentation in a beverage
Beverages can also be fermented.
For kombucha, sweetened tea is fermented with the help of a community of various microorganisms. A so-called SCOBY—a culture of bacteria and yeast—is frequently used for this.
During fermentation, the microorganisms transform components of the beverage. This produces organic acids, among other things, as well as small amounts of other fermentation products.
The exact historical origin of kombucha cannot be reconstructed beyond doubt. The beverage is frequently associated with East Asian traditions. What is certain, however, is that today kombucha is a good example of how a traditional fermentation technique is being reinterpreted in a modern form.
Fermentation varies globally
Kimchi from Korea, yogurt from various regions of Asia and Europe, or sourdough bread show only a small snapshot.
All over the world, humans have used fermentation to transform their respective staple foods.
For example, this resulted in:
- Sauerkraut from fermented cabbage
- Miso from fermented soybeans and other ingredients
- Tempeh from soybeans
- Kefir from milk
- Sourdough from grain
- Fermented fish products
- Cheese and fermented milk products
- Vinegar
- Wine and beer
- Various fermented vegetables and beverages
Which form of fermentation developed depended heavily on the climate, available raw materials, and regional traditions.
That is precisely why there is no "single" fermentation cuisine today.
Why was fermentation so valuable to humans?
The historical significance of fermentation cannot be reduced to a single benefit.
-
Foods could be preserved differently.
Before refrigerators existed, methods for preservation were especially important. Fermentation, together with salt, drying, or cool storage, helped to make food usable over a longer period. -
New flavors were created.
Mild cabbage turns into tart sauerkraut, milk into yogurt, and simple dough into aromatic sourdough bread. Many flavor profiles that we take for granted today only emerge through fermentation. -
The properties of raw materials change.
Microorganisms transform specific food components during fermentation. As a result, texture, aroma, and composition can change. -
Fermentation helped utilize seasonal raw materials.
Large harvests could be processed instead of having to be consumed exclusively when fresh.
Over the millennia, this practical technique evolved into an important component of many food cultures.
From experience to microbiology
Throughout most of history, people did not know why fermentation worked.
They only knew how it worked.
Starters were passed on, vessels were reused, and successful methods were repeated over generations.
It was not until the 19th century that a more precise scientific understanding developed regarding the role microorganisms play in fermentation processes. The realization that yeasts, for example, are living organisms and actively involved in fermentation fundamentally changed the perspective on traditional manufacturing processes.
This marked the beginning of the transition from empirical fermentation to controlled microbiology.
How does fermentation work today?
The basic idea has remained the same, but control over the process is significantly greater.
In food production, precisely selected starter cultures can be used today. Temperature, time, humidity, oxygen supply, or pH value can be controlled exactly.
This allows manufacturers to reproduce the properties of a product much more reliably.
In addition to classical foods, fermentation has also become an important technology in the food industry and biotechnology.
The ancient cultural technique has therefore by no means disappeared; it has been scientifically advanced.
Why fermentation is so popular again today
Interestingly, even in a highly technical food world, many people are interested in very traditional forms of fermentation once again.
Sourdough starters are maintained at home, vegetables are fermented by oneself, and products like kimchi or kombucha have long been available outside their original regions.
There are several reasons for this.
Fermentation combines craft with a spirit of experimentation. A product visibly changes over several hours or days. At the same time, complex flavor profiles are created that are difficult to replicate using other methods.
Added to this is the growing interest in microorganisms, the gut microbiome, and fermented foods.
A distinction is important here, however: a fermented food does not automatically contain living microorganisms, nor is it automatically a probiotic food. For instance, the microorganisms in sourdough are mostly killed during baking.
Who invented fermentation?
No single person or culture can be named as the inventor of fermentation.
Very likely, different societies discovered fermentative processes independently of one another. Microorganisms occur naturally in our environment, so fermentation could occur long before humans understood what was happening at a microbial level.
What was the first fermented food?
This question, too, cannot be answered definitively.
Archaeological findings point to very early fermented beverages made from grain. At the same time, fruits, milk, and grain porridges were likely also spontaneously fermented early on.
The archaeological evidence known to date shows one thing above all: fermentation has accompanied human nutrition for many thousands of years.
FAQ:
Is sourdough a fermentation?
Yes. Sourdough is created through the activity of microorganisms, particularly lactic acid bacteria and yeasts. However, finished baked bread generally no longer contains living fermentation cultures, as they are inactivated by the high temperatures during baking.
Is yogurt fermented?
Yes. In yogurt production, specific lactic acid bacteria convert components of the milk. Yogurt is therefore a classic example of a fermented food.
Are kimchi and kombucha also fermented?
Yes. With kimchi, lactic acid bacteria in particular take on central roles during fermentation. Kombucha, on the other hand, is created by a community of yeasts and bacteria.
The microorganisms and fermentation pathways involved therefore differ—but the basic principle remains the same: microorganisms intentionally transform the starting food item.
Conclusion: An ancient technique that remains relevant today
Fermentation is one of the oldest forms of food processing. Long before humans could view microorganisms under a microscope, they learned to use their activity for the production of food.
From this experience came sourdough, yogurt, cheese, fermented vegetables, beverages, and numerous regional specialties.
Today, we understand much more precisely what happens during these processes. At the same time, the basic idea has survived surprisingly well: microorganisms are given suitable conditions—and transform a raw material into something new.
Perhaps it is precisely this connection between millennia-old tradition and modern microbiology that explains why fermentation is receiving so much attention again today.
