The rise of northern Europe as a great economic power was inextricably linked to salt. This transition of wealth from the Mediterranean to the Atlantic world was driven, ironically, by religious observance. In the early Middle Ages, the Catholic Church dramatically expanded the number of “lean” days when meat consumption was forbidden, requiring the populace to rely on preserved fish. The Lenten fast, established in the fourth century, was extended to forty days, and all Fridays, commemorating Christ’s crucifixion, were included.
These food prohibitions, which covered roughly half the year, were strictly enforced. Under English law, eating meat on a Friday carried the penalty of hanging, a law that remained until Henry VIII broke with the Vatican in the sixteenth century.
This immense, state-enforced demand for non-meat food established the salt fish trade as one of the most profitable markets in Europe. Before the North Atlantic fishing boom, one of the earliest “lean day” foods available to the European peasantry was craspois, also known as craspoix or grapois. This food consisted of strips of the fattier parts of whales, salt-cured like bacon. French merchants referred to it as lard de carême, or “lent blubber,” and it was one of the primary provisions for the peasantry on days when other red meats were not allowed. Though often tough and hard, even after a full day of cooking, and typically eaten with peas, this salted whale blubber was considered a luxury product in England, where high tariffs were paid by Rouen merchants selling it to the English. The tongue of the whale was considered a great delicacy for the rich.
The Basques and the White Flesh
The Basques, living on the Atlantic coast in their small, mountainous land partly in Spain and partly in France, were unique in Western Europe; by the seventh century A.D., they were the only people not speaking an Indo-European language. They were also the first commercial whale hunters, preceding all others by several centuries. The earliest record of commercial whaling is a bill of sale from A.D. 670 for forty pots of whale oil sent to northern France from the Basque coastal province of Labourd.
Throughout the subsequent centuries of commercial whaling, the oil boiled from whale fat was the most consistently valuable part of the whale.
However, Basques soon found a far more profitable commodity: Atlantic cod. Cod is an ideal fish for preservation because its white flesh is nearly fat-free. Since fat resists salt and slows its penetration, oily fish must be pressed tightly in barrels, but cod can be simply laid in salt. Cod and related species like haddock and whiting can also be air-dried before salting, a process that yields a superior cure difficult to achieve with oily fish like anchovy or herring.
The fishing nations of northern Europe all desired to participate in the lucrative salt cod market. They possessed the fish, but they desperately needed salt.
The Vikings and the Salt Route
The Vikings may have been pivotal in solving the salt problem for the North. While they had previously experimented with solar evaporation saltworks in Normandy in the seventh century, the northern climate (too much rainfall and insufficient sunlight) rendered these operations unproductive.
The island of Noirmoutier, barely detached from the French mainland at the Loire estuary, became an early Viking base. This region features a natural tidal swamp periodically flooded by strong tides, bringing a fresh supply of seawater. It is not known exactly when Noirmoutier and the nearby mainland marshes of Bourgneuf and Guérande began constructing systematic artificial ponds, but production significantly increased around the ninth or tenth century, following the Vikings’ arrival. The Vikings had previously seen successive artificial pond systems in southern Spain. Although Breton historians dispute the claim, preferring to credit the Celts with the invention, it is certain that the Vikings were the first to trade this salt to the Baltic and other northern nations, establishing a critical salt route in the late Middle Ages and Renaissance.
The Bay of Bourgneuf, located on the southern side of the Brittany peninsula, became a leading salt center because it was the most northerly point in Europe with a climate suitable for solar-evaporated sea salt. The area, including Guérande, Bourgneuf, and Noirmoutier, also benefited from its location on the Atlantic coast, connected to the Loire River for inland transport. The salt from this region, sometimes green, gray, or black, was known throughout northern Europe as “Bay salt” and was inexpensive and large-grained, making it perfect for curing fish.
The Breton fishing ports held a crucial advantage because France had granted the Celtic duchy of Brittany an exemption from the hated gabelle, the French salt tax, to facilitate its entry into the kingdom. This provided them easy access to the untaxed saltworks of Guérande, Noirmoutier, and Bourgneuf. Conversely, La Rochelle, previously a minor Atlantic port, became the leading Newfoundland fishing port because of its proximity to the Ile de Ré saltworks. Records show that between John Cabot’s voyage in 1497 and 1550, more than half of the 128 documented fishing expeditions from Europe to Newfoundland departed from La Rochelle, their ships’ holds filled with salt from Ile de Ré.
The Breton salt makers, known as paludiers (swamp workers), crafted ponds out of the grassy swamp. They harvested two types of salt: the coarse, gray salt and fleur de sel. When a dry wind caused crystals to form on the water’s surface, women would use long poles with a board to skim the lighter, finer fleur de sel. This was considered women’s work, requiring a “delicate touch,” although the baskets of light salt they carried on their heads weighed ninety pounds.
The name Guérande is derived from the Breton name Gwenn-Rann, meaning “white country”.
The Nordic Dream and the Herring Shoals
In Sweden, the scarcity of salt led to folklore, such as the custom of girls eating heavily salted porridge or pancakes and sleeping without drinking, hoping their future husbands would appear in a dream to offer water. The “Swedish dream” was salt, as Sweden had abundant herring but lacked the salt needed to cure it.
After salt cod, preserving herring became the second major commercial use of salt for the European Lenten diet in the thirteenth and fourteenth centuries. Herring is an oily fish, unlike cod. The rise of the herring trade coincided with Atlantic nations gaining economic power over Mediterranean ports.
Herring swim in vast masses called shoals, which can provide an ample catch once located. However, herring shoals search thousands of miles for food, meaning a spot previously teeming with fish might suddenly be empty for years, a cataclysmic event often blamed on local sins, like adultery.
In 1350, Wilhelm Beuckelzon, a Dutch fisherman, was credited with inventing the technique of pickling herring in brine without drying, a method that prevented the fat from turning rancid from air exposure. While European powers, including Charles V, paid homage to Beuckelzon, the myth is largely bogus; Scandinavians, English, Flemish, and French had been barreling herring in brine for centuries by his time.
The salt fish market was primarily the “low end,” supplying lenten food for the poor. An estimated 60% of all fish eaten by Europeans between the sixteenth and eighteenth centuries was cod, with herring making up a significant portion of the rest.
Cured herring had an even lower social standing than salted cod. Yet, supplying the poor with herring created massive fortunes, limited only by access to salt.
In the gray, rainy northern climate, salt makers adapted. In northern Holland and southern Denmark, peat salt was produced by burning seawater-impregnated peat, called zelle, dug from tidal flats. This process, however, consumed vast amounts of forest for fuel. Norwegians improved this technique by pumping saltier water from the sea depths using piping made from hollowed tree trunks.
Smoking was another Northern solution to salt scarcity, as it requires less salt for preservation. Red herring, a famous English export, is soaked in a brine of salt and saltpeter, then smoked over oak and turf. In Sweden, a light cure was devised for Baltic herring, resulting in surströmming. Since the Baltic Sea is less salty, the herring is smaller and leaner. Surströmming is chemically fermented, not rotten, as the brine prevents putrefaction until fermentation begins. It is still notoriously pungent, smelling like fermented cider mixed with Parmesan cheese and ancient bilge water.
The Hanseatic League and Commerce
The Hanseatic League, a commercial and defensive confederation of merchant guilds and cities in Northern Europe, came to control the lucrative northern herring trade. In the fourteenth and fifteenth centuries, Skanör and Fasterbö in southern Sweden became major herring producers. They imported salt from the Hanseatic German port of Lübeck and exported their cured herring back to Lübeck for marketing across Europe.
At its peak in the fifteenth century, the Hanseatic League commanded 40,000 vessels and 300,000 men.
The Hanseatics were known as Easterlings because they came from the east, and this is the origin of the word sterling, meaning “of assured value”. They ensured quality throughout the barrel, fighting against the practice of unscrupulous merchants who mixed rotten or inferior fish with ashes-laced peat salt, which was common before their control.
Central Europe and the Hapsburg Pickle
In Central Europe, salt production was crucial to provisioning vast territories. Much of the region’s salt eventually fell under the control of the Hapsburgs. From the eleventh century, the Pallovicino family controlled the brine wells at Salsomaggiore in the Po Valley. But the takeover of these thirty-one wells by the city of Parma in 1318 marked a shift of power from the feudal lord to the city government. The region became famous for prosciutto di Parma.
The Hapsburg family, whose rule spread across Central Europe, controlled salt mines from their beginnings in tenth-century Alsace. They gained control of the Danube River, Silesia, Hungary, and the southern Polish region of Galicia. The Polish Crown earned one-third of its annual revenues from the Wieliczka and Bochnia salt mines near Cracow. These mines, which supplied salt with a water route via the Vistula River to the Baltic, competed with sea salt from France and Portugal.
The Hapsburgs controlled salt in Austria’s Salzkammergut region, including the massive Dürnberg mine. Rock salt was extracted from Dürnberg, leading to the preservation of miners’ bodies dating back to 400 B.C., along with their tools and clothes. Hallein, pressed between the Dürnberg Mountain and the Salzach River (a Danube tributary), sent cylindrical salt molds by barge down the Salzach to the Danube for trade in Germany and Central Europe.
Salt was essential for curing meat and vegetables for the long, barren winters of the Hapsburg Empire and Russia. In Russia, a common meat ration was solonina, or salted beef. The Russian recipe advised rubbing freshly slaughtered beef with salt mixed with saltpeter and spices before packing it into small oak barrels.
Central Europe also relied heavily on lactic fermentation, commonly known as pickling, for vegetables like cucumbers and cabbage. The importance of this practice is highlighted by the Lithuanians, who recognized a guardian spirit of pickling named Roguszys. Sauerkraut (sour grass), originally a dish for special occasions, was made by chopping cabbage and salting it in barrels with various spices. The Polish national dish, bigos, is essentially sauerkraut to which meat, bacon, and pickled fruits are added.
The French Gabelle: State Monopoly as Disaster
In France, the tax on salt, the gabelle, proved to be arguably the greatest disaster of royal administration. The tax system was so despised that its eventual repeal helped launch the French Revolution.
The concept of the nef, a large, ornate, jeweled vessel holding salt, symbolized both the ruler’s health and the stability of the nation in royal France. The absence of a saltcellar on a Roman banquet table was seen as an unfriendly act. Similarly, careful etiquette governed handling salt: it was considered rude, even unlucky, to touch it with the fingers. The Shulchan Arukh (The Prepared Table), a sixteenth-century Jewish law book, specified that salt could only be safely handled with the middle two fingers; using the index finger risked turning the server into a murderer.
The French Crown, under Louis IX, began controlling salt production for royal revenue in the Mediterranean Rhône estuary at Aigues-Mortes (“dead waters”) in 1246. Louis wanted salt revenue to finance his Crusade. This idea of state-controlled Mediterranean saltworks eventually evolved into the rigid administration of the Grande Gabelle.
Jean-Baptiste Colbert, Louis XIV’s finance minister, codified the tax structure into six unequal zones in 1680. The Pays de Grand Gabelle (core France) contained only one-third of the French population but paid two-thirds of the state’s salt revenue, making residents there the most angered by the tax.
The price disparities created massive incentives for smuggling. In 1784, Jacques Necker, a Swiss banker advising the government, reported that a minot of salt (107.8 pounds) cost 31 sous in Brittany, 81 in Poitou, 591 in Anjou, and 611 in Berry. Smugglers, known as faux sauniers, used hidden coves and islands on the Loire River. By 1773, 3,000 troops were stationed on the Loire to stop salt smuggling. One smuggling ruse involved shipping “green salt cod,” which required ample salt for preservation, in thick layers, with merchants sometimes bribing officials with fish to expedite their journey past inspectors.
In 1789, the revolutionary legislature repealed the gabelle, calling the salt tax “odious”. All trials of violators were annulled and prisoners were set free. However, Napoleon reinstated the gabelle in 1804, eliminating the exemption for Brittany. The tax remained part of French administration until 1946.
Salt and Health
Salt’s role in health and medicine also remained prominent. In the early Middle Ages, farmers in northern Europe learned to save their grain harvest from a poisonous fungal infection called ergot by soaking the grain in salt brine. This belief in salt’s protective power led Anglo-Saxon farmers to include salt in magic ingredients placed in a plow when they chanted to the earth goddess for good crops.
Roman physician Galen (A.D. 130 to 200) noted that salt fish was considered both a food and a medicine. The Chinese were aware of saltpeter (potassium nitrate) as a salt for gunpowder. In the 18th century, English physician William Brownrigg noted that while rock salt and white salt were inferior for curing fish, they were good for cattle.
The development of chemistry in the 17th and 18th centuries began to reveal the true complexity of salt compounds. Sir Humphry Davy, a self-taught English chemist, isolated sodium (the seventh most common element on earth) in 1807 through electrolysis. He also isolated chlorine (a greenish gas) in 1810, naming it after the Greek word for greenish yellow. Chlorine became the basis for liquid bleach, a major element in the British textile industry, and later, for chemical warfare, including mustard gas, which caused 800,000 casualties in World War I.
Meanwhile, other chemists identified different mineral salts: Johann Rudolf Glauber isolated hydrated sodium sulphate, known as Glauber’s salt (used today in textiles and metallurgy). Nehemiah Grew isolated magnesium sulphate, known as Epsom salt (used medicinally, in explosives, and in textiles). These discoveries established that “salt” was a specific group of substances, not merely common table salt, but a compound resulting from the reaction of an acid and a base. The word chemistry was first used in the early 1600s, though it only became an independent field of research toward the end of that century.