The history of bread is almost as old as the history of humanity. Bread was first discovered about 14000 years ago in the middle East region known as the fertile crescent ("crescent" means "croissant" in French, aptly named in the context of this article :). This region is often considered as the birthplace of civilization: humans settle around fixed locations, start agriculture and the first cities are born. One of the first grain crop cultivated was wheat and the first food derived from wheat was...bread! The first bread loaves were believed to be flat (unleavened) and were often baked over an open fire or under amber and sand.
Sourdough bread fermentation was probably discovered by chance in Egypt during the times of the pharaohs, about 3500 years ago. It's sometimes referred to as "the sourdough miracle", although I think with the right conditions, the phenomena would have eventually been witnessed by curious humans.
Note: in this article, I will use the term "sourdough" as "naturally fermented with wild yeast". Before the invention of commercial yeast, this was the case for all leavened bread.
From that initial "seed" the news (and the knowledge) spread rapidly from one family to the next, then to the entire community. In fact, based on the remains that were found in major sites like Giza, bread was believed to be the main diet element of the population at that time. It very likely fueled the slaves who built the pyramids.
Note that they did not have Kitchen Aid mixers back then, so dough was kneaded with the feet. That would have certainly contributed in some interesting ways to the mix of bacteria in the overall fermentation process.
From Egypt, bread making spread (no pun intended :) to its trading neighbors, the Greeks and the Romans. In Greece, bread was mostly made from home. Since every aspect of ancient Greek life was tied to religion, there had to be a goddess of bread. Her name was Demeter. Demeter also happened to be the goddess of agriculture and grain and also sometimes revered as the same god as Gaia "mother earth". Some bread was kept aside as god offerings, but during the time of Plato, bread was part of the main diet. The average Athenian ate 800gr of bread, mostly barley. The rich Athenians preferred white flour bread, since it was deemed purer and safer to eat. Barley was deemed fit for the poor, the sailors and the slaves. We'll see that trend continuing until all the way until the industrial revolution.
Ancient Rome saw the creation of the first regulated bakery corporations. A well preserved bakery was discovered among the ash covered remains of Pompeii. Yeast was made once a year at harvest time with fermented grape juice and bread dough. Various grades of flour led to different kinds of bread: panis siligineus for the rich, panis nauticus (a kind of hard biscuit) for the sailors, and at the bottom of the scale, panis furfureus for the dogs! Despite wide range variation in quality, bread was a central part of the Roman diet: each bread citizen received an allowance of 33 kgs of grain per year, that later became a dole of bread and olive oil. Possibly the first usage in history of a GMI (Guaranteed Minimum Income)?
Bread subsequently plays a central part in the western world monotheist religions, more specifically, Judaism and Christianity. In particular, the Matzo bread used by Jewish people is a reminder that upon fleeing Egypt, the Jewish people led by Moses had to leave their starter behind. That's why Matzo is a flat unleavened bread.
In Christianity, the bread Miracle is celebrated, as Jesus is able to feed a crowd of several thousand hungry followers with a basket of bread. Turns out it might have very well been a container of starter, that eventually resulted into thousands of loaves.
Another hotly debated episode among bread purists is the Last Supper, when Jesus shares the bread among his disciples. It is often represented as unleavened bread, but based on the specific time of the supper (before or during the Jewish Passover), it might have been leavened. Catholics adopted the first one (Eucharistic wafer), while Christian Orthodox prefer the latter.
Greeks living in Marseille introduced sourdough bread in Gaul (contemporary France) in the 4th century BC. During the tumultuous early middle ages, the tradition of bread making was kept in the monasteries. Bread yeast was made from beer foam. The Royalties and nobles did not eat the bread crust, considered unsafe and they certainly preferred white flour bread. Bread was often used as a plate and eaten or left for the dogs at the end of the meal. Western and northern Europe saw the development of water mills for grinding the flour.
Bread was prepared at home in the villages but baked in the communal oven, which was a way for the local lord to levy a hefty tax. In fact, it is an increase in the price of bread that eventually led to the French revolution in 1789. The protest was initially led by women in Paris, who were struggling to feed their family during a time of famine.
French scientist Louis Pasteur discovered leavening in 1857. He also discovered the existence of germs. The manufacturing and commercial use of yeast (cream) came shortly after during the industrial revolution that started in the UK during the late 19th century (active dry yeast was invented much later in the US, during world war II: Fleichmann's yeast, still around to these days). In order to support all the coal and iron mining efforts, large scale production of food had to follow. London sees the birth of the first mechanized bread production and the first tasteless uninspiring white bread that the country eventually widely adopted, produced by the "Aerated Bread Company" (the name says it all). At that time, mass-produced white bread also becomes the most affordable bread.
Eventually, industrial bread production becomes more sophisticated as it moves across the Atlantic to North America. Additives to recreate the taste of sourdough, vitamins (calcium and vitamin D) to palliate the loss of nutrients from white flour refining, preservatives for longer shelf life, bleaching to keep color all become common place. Sourdough seems like a distant history lost behind the thick walls of some European monastery.
Sourdough first lands in the US during the California Gold rush. San Francisco's famous Boudin bakery opened in 1849. Gold prospectors in the US and Canada, always keeping a starter close to the vest during the cold months of winter, became known as "Sourdoughs".
Some bay area scientists investigated if they could pinpoint the bacteria that was responsible for the so-called "unique" sour taste of San Francisco's sourdough. They came up with (what else) "Fructilactobacillus Sanfranciscensis", which was later found commonly in starter worldwide. So much for the uniqueness!
The revival period: after falling out of favor for the popular white bread for centuries, sourdough bread and whole wheat have been making a comeback with a vengeance in the last couple of decades. The Slow food movement started in Italy in the mid 1980s as an alternative to fast-food. It primary goal was to go back to the roots of food making, and reconnect with the traditional ways in the kitchen and around the table. In California, Alice Waters of Chez Panisse has been spearheading the movement. More recently, sourdough bakeries like Tartine in San Francisco, Acme Bread in the bay area and Poilane in Paris have become the reference for the new wave of sourdough, high quality (and expensive) bread.
So we now have come 180 degrees from where we started from: the mid to high income educated folks look for whole wheat bread (organic sourdough if possible) while the rest of the population eats industrialized, cheap white bread made from commercial yeast (at least that's the case in the US). Is the popularity of quality sourdough bread that accelerated during the Covid pandemic just a fad? Let's sure hope this trend will continue so that sourdough healthy traditional bread becomes more widely available. History will tell.