The Importance of Salt

Salt is a biological necessity of human life. But we live our daily lives practically unaware of this basic biological fact. Most of our food already has salt added to it: check the labels on almost any prepared food in the house. But if you are in the habit of baking your own bread, or cooking your own porridge, it's immediately and disastrously obvious if you forget the salt.

In ancient times, salt (or the lack of it) could drastically affect the health of entire populations. Trade in salt was very important, and salt was valuable enough to be used as currency in some areas. The Latin phrase "salarium argentum," "salt money," referred to part of the payment made to every Roman soldier, and the word has been carried down the ages into the English word "salary". Everyone must have salt, so it has been a commodity much abused by attempts at monopoly, by individuals, corporations, cities, and nations. The city of Rome may have begun as a salt-trading center, like Venice after it. Certainly the salt traders of the Roman port of Ostia raised the price so high that the state was forced to take over the industry about 506 BC. Man-made salt-ponds along the Mediterranean shore date back to Roman times, and it is inevitable that we will find older ones. Salt was already being mined in the Alps when Rome was founded.

Salt was taxed by governments from the ancient Chinese and Romans to late medieval Burgundy, where salt was taxed at more than 100% as it came from the salt-works. Extended to the whole of France when Burgundy was absorbed, the notorious salt tax "la gabelle" became necessary to the government. Cardinal Richelieu said that it was as vital to France as American silver was to Spain. The repeal of the salt tax was a major goal of the revolutionaries of 1789, but Napoléon restored it as soon as he became Emperor, to pay for his foreign wars: and it continued until 1945. It is said that income from a salt pan in southern Spain largely financed Columbus' voyages. In the United States, the State of New York financed the Erie Canal with its salt tax!

Food storage is vital for any society. We have refrigeration, freeze-drying, and canning as our major ways of preserving food, and it's difficult to envisage life without them. Whether it is hunted, gathered, or grown and harvested, food rarely is available when it is needed, unless it is somehow stored. Today, with refrigeration and effective transportation, the problem seems rather trivial, but before the 19th century, effective storage often made the difference between life and death.

In arid climates, food can effectively be stored by drying. But in any normal humidity, fungus and bacteria can rapidly destroy stored food. Even where food can be stored in ice during a winter, it quickly rots as it thaws in the spring. Documents from northern Europe, and especially from 16th century Sweden, give some clue about the severity of the problem, and its solution.

In a medieval society, with relatively poor transportation systems, villages and counties had to be close to self-sufficient in food. If a bad harvest occurred, there had to be enough food stored to mitigate a potential disaster. Medieval Sweden provides an example of the way in which an agricultural society dealt with this. Good-quality arable land was scarce, and had to be used for crops. That meant that grazing and foraging animals, mainly cattle and pigs, were turned out into the local woodlands for the summer to forage for grass, browse, roots, and nuts. A relative shortage of winter fodder in turn meant that surplus animals would best be butchered before the weather drove them indoors. In medieval England the annual slaughter was traditionally around Martinmas, St Martin's Day (10 November), but it was earlier in Sweden. In turn, that meant that fresh meat was readily available only at that season, and that fresh protein in the form of milk and butter was only available in winter from cows kept in shelter. In addition, taxes were often paid in kind rather than money, and that meant that the landlord had to be given foodstuffs that could be stored.

The response of the Swedes was to preserve almost all their food, and to use salt to do it. Beef and pork were salted and dried as joints, hams, and sausages. Butter was salted. Typically it took a pound of salt to preserve 10 pounds of butter (housewives were taught how to remove the salt before the butter was used). Fish, whether freshwater or from the sea, were salted and dried. Bread was hung up to dry. In 1573, the servants of King Gustavus Vasa ate 102 kg (224 pounds) of beef and pork, but 99 kg of it (218 pounds) was salted and dried. They almost never had fresh meat. The King issued an order to release 3-year-old tax butter from the stores for some men hired to work at the castle, and ordered the sale of 4-year-old (barley) malt because it was starting to get weevils in it. He ordered the peasants to store their butter and meat in the fall, after the annual slaughter, but he also ordered them not to eat any of it for 12 months (they should be eating the previous year's food during that time).

There were three interesting consequences of this way of life. First, it made the country much more able to tolerate the occasional disastrous harvest, and the second was that it promoted the consumption of enormous quantities of beer, to go with the food, which even when soaked and cooked was still very salty. Prince John of Sweden wrote to his father King Gustavus saying that five and a half pints of beer a day was not enough for the soldiers, and that the prince had raised their ration to 8 pints a day and 11 on Sundays. More important, it meant that Sweden had to import large quantities of salt. In 1368, for example, 23% of the goods shipped from Lübeck to Stockholm consisted of salt, and that proportion did not change: in 1559, 25% of Sweden's imports consisted of salt (and 19% was hops, for brewing beer that lasted longer without spoiling). Salt was a strategic commodity. Especially in wartime, Sweden had to be careful to safeguard the shipping routes that delivered this vital substance to her people.

Maybe you think that the Swedish medieval diet is outrageously old-fashioned, perhaps quaint, certainly faintly repulsive. So let us move to the Old South in 1864. Each Confederate soldier was supposedly provided with starch (26 pounds of coarse meal, 7 pounds of flour or biscuit, 3 pounds of rice), protein (10 pounds of bacon), and salt (one and a half pounds). Bacon was the meat of the South, and every pound of it required salt. Horses need salt too. The historian Ella Lonn devoted an entire book to the problem of salt in the Confederacy during the Civil War. The salt supply was a problem throughout the war, and we will never know whether the salt shortage that preyed on the minds of the Southerners translated into a vital reason for their defeat.

We know that the Confederate soldiers were hungrier than the Northerners throughout the war. We shall never know whether the hogs that were not slaughtered because there was no salt to preserve them took the edge off the Confederate troops, or whether the salt that was not available for the horses took the edge off the cavalry. "What hogs we have to make our meat, we can't get salt to salt it," wrote Mrs Sarah Brown to Governor Pettus of Mississippi in December 1861. In 1862, Governor Brown of Georgia wrote that only half of the meat of the State could be saved for the 1862-1863 season.

We do know that that most intelligent and brutally efficient of the Northern Generals, Sherman, had no doubt about salt. It was as important as gunpowder, he declared. "Without salt they cannot make bacon and salt beef," and, "Salt is eminently contraband, because [of] its use in curing meats, without which armies cannot be subsisted." Sherman sent a captain for trial on a charge of aiding the enemy, because he had allowed salt through the lines to the Confederates. The Union forces were sent orders to destroy salt stores and salt works wherever they were found. In November 1863, General Burnside noted in a despatch to Grant that Lee had placed a strong defensive force in front of Saltville [Virginia]. Grant understood the significance of the deployment. In December 1863 he wrote to General Foster, "If your troops can get as far as Saltville and destroy the works there, it will be an immense loss to the enemy." In the event, the Confederates guarded the works so well that the Union Army did not take (and destroy) the salt works until December 1864. General Burbridge boasted that the loss of Saltville would be "more felt by the enemy than the loss of Richmond." Meanwhile the North, even with salt sources of its own, imported 86,208 tons of salt from England in 1864 alone.

Medieval Sweden and the Confederate South may be extreme examples, but the importance of salt in history was much greater in the past than it is today, when salt is cheap and ubiquitous. Salt was often as important for food storage as it was as a direct nutrient.

Sources of Salt

Salt can be obtained most simply by collecting it from natural evaporation pans, such as rock crevices along dry coastlines, or in salt pans in desert regions. It is a short step to constructing dikes to make larger shallow pans along coasts, and then to heating salt water in pots. It does take a great deal of energy to evaporate salt water to yield salt. Along sunny dry coastlines, solar energy is free to the patient person. But in wetter, cooler areas, salt water must be heated to evaporate, and the cost of fuel may become the dominant element in the economics of production.

However, inland there are occasional salt springs, and natural outcrops of salt-bearing rocks. Natural salt springs often yield brines that are more concentrated than sea water, and yield purer salt (sodium chloride) than seawater brines. The difference can be crucial, because the magnesium chloride present in small quantities in sea salt can actually slow down the rate at which meat is salted and therefore prevented from decay. Sea water can be processed to extract the magnesium as the brine is boiled, but that takes skill and labor, and fuel. Natural salt from springs usually had a competitive edge over sea salt.

The relative rarity of salt springs often provided an important geological resource to an inland community or area. For example, Austria and Germany happen to have many outcrops of salt-bearing rocks, a particularly fortunate circumstance in an inland region with a generally damp climate. Names containing "salz" and "halle," such as Salzburg ("salt city"), Salzkammergut, Reichenhall, Halle, Hallein, and Hallstatt, as well as the old Austrian/Polish province of Galicia, identify some of the salt-bearing areas.

The Maya made salt at Salinas de los Nueve Cerros, Guatemala. This site lay where salt springs flowed into the river, giving easy trading access to downstream customers. This site was the only large-scale source of salt for the interior Lowland Maya. The technology included solar evaporation and firing of brine from salt springs in special ceramic bowls that are the largest ever found in Maya sites.

The highly organized salt trade of China was observed by Marco Polo, who recorded that the major item of trade on the Yangtze River was salt, shipped upstream from the coast (especially from the city of Hangchou) to the interior cities. The Chinese produced salt by many methods: they evaporated it, boiled seawater, and pumped brine from wells drilled into salt beds. Modern oil-drilling traces its technological roots back to Chinese methods originally evolved for salt production.

Salt in Medieval and Renaissance Europe‹Inland Europe
Central Europe lacked the access to shipping routes that made an international salt trade possible round the coasts of northern Europe. Salt could be economically transported only over short distances, and local sources of salt became important commercial centers, often wielding a good deal of political power.

From about 1000 BC onward (and possibly since 2500 BC, and maybe for unrecorded millenia before that), a brisk salt-mining and salt-shipping trade was centered on the valley of the Salzkammergut, in what is now Austria. The surface deposits were worked out by 1000 BC, and the salt miners drove galleries 400 meters into the mountain side, reaching depths below the entrances of 100 m. Because salt is a good preservative, we have a good idea of the working tools and working conditions, and even the miners' diet (from preserved feces). A perfectly preserved body was found in 1735 and given a Christian burial! Some of the caverns the salt miners excavated with their bronze tools were 12 m by 12 m, a meter high, and supported by timbers. The salt was carried out in leather rucksacks, and the miners wore woollen clothes and leather slippers. They ate well: millet, barley, beans, and apples.

Salt in Austria and Bavaria
The great salt center of Reichenhall, in southern Bavaria, operated in Roman times, but was destroyed later, possibly by Attila the Hun but more likely by the German Odoacer. It was rebuilt and became the concession of the Bishop of Salzburg, who derived a great deal of power and money from the salt trade‹the Bishops were promoted to Archbishops. About 1190, however, someone opened a competing salt works at Berchtesgaden nearby, without the Archbishop's approval, and a major quarrel between Church and State erupted, with the Archbishop and the Emperor in conflict. The Church lost, and in 1198 the Bavarian salt works passed into the control of the Duke of Bavaria. Reichenhall's production peaked at about this time, and it lost out in competition with the new salt works opened to the south by the persistent Archbishops of Salzburg, but it remained important for several hundred years. [Reichenhall still produces salt today, although a lot of its income now derives from tourism and from allegedly therapeutic salt baths or Heilbaden.]

Thwarted in Bavaria, the Archbishop of Salzburg turned to salt springs closer by, and a new industry sprang up at Hallein, first mentioned in documents in 1232. By 1300 its production had outstripped that of Reichenhall, and as it was situated closer to the Danube, it was able to ship salt as far as Bohemia, as well as into Austria and Bavaria.

The Archbishop gradually bought up shares in Hallein, and by the early 16th century he held them all. However, the crown of Bohemia passed into the Habsburg family, and from the early 1600s, the great market of Bohemia was closed to the Archbishop. The other Austrian salt works were small at first. In the Salzkammergut, salt springs emerged from horizontal tunnels in the valley sides, which, although the locals did not know it, were the ancient galleries into the old flooded salt mines that had been worked in prehistoric times.

The salt works at Hall, in the Tyrol, provided a power base for its owners, who were the local Hapsburg Dukes from 1363. The Dukes would sell salt to the Swiss, then use the profits to pay for the Hapsburg campaigns against the Swiss!

Salt production was always limited in Austria by fuel shortage. As boiling houses used up the local timber, they had to be moved, and fuel was a problem until modern times. In 1770 there were even flumes running down the mountain sides, used not for water supply but to float down billets of timber for the boiling houses. Since fuel ran out at Hallstatt very early, the Emperor built a wooden pipeline to take the brine from the ancient mines down the valley to Ischl: it crossed the Gosau on a bridge.

Salt played a great part in the politics of the region after 1600. Salt was produced by three major players, Austria, Bavaria, and the Archbishop of Salzburg. The Austrian Empire grew to include Bohemia and Moravia, and this salt-less region became a captive market for the Austrian salt producers, with much tax revenue accruing to the Emperor. Salt was a state monopoly, the Salzmonopol, "the brightest jewel in the possession of the Hofkammer," and around 1700 provided about 10% of the total revenue of the state.

The Habsburgs would regularly use the salt income as collateral for raising money quickly in times of military emergency. They did it first when Bohemia revolted in 1618 in the Defenestration of Prague, and Protestant forces besieged Vienna. Emperor Ferdinand II mortgaged his salt revenues to pay for the Catholic army that saved Vienna and won the decisive battle of the White Mountain in 1620. The salt revenue of the salt mines of Wieliczka paid for the heroic Polish army under King John Sobieski that rescued Vienna during the Turskish siege of 1683. (In a strange-but true paradox, the Wieliczka salt revenue had passed to the Habsburgs in return for their assistance to the Poles in the Swedish invasion of 1657!) Salt was a state monopoly in Bavaria also. Both Austria and Bavaria sought to promote their own exports and protect their domestic markets from salt imports. (There was a flourishing trade in contraband salt.)

In 1611 the Archbishop of Salzburg was forced to market his salt through Bavaria, so the rivalry now had only two players. Given that Austria and Bavaria between them controlled all the major salt sources in Central Europe, it is difficult to understand why they did not cooperate to form a cartel. A brief agreement, the Rosenheimer Salt Trade Agreement, was set up in 1649, but lasted for only 40 years. The centerpiece of Bavarian foreign policy became a campaign to sell salt effectively to her western neighbors, given that Austria could sell hers throughout the growing Austro-Hungarian Empire. It is not a coincidence that Bavaria consistently fought on the French side against the Austrians in the War of the Spanish Succession in the early 1700s and during the Napoleonic Wars in the early 1800s.

The Mediterranean

The great trading ports of the Mediterranean dealt in salt as well as spices and textiles. Not surprisingly, the greatest of them, Genoa and Venice, not only traded in salt but fought for supremacy over the trade.

Salt can be made in almost any suitable seashore locality in the Mediterranean. So although it is possible to envisage a trader's cartel, it is much more difficult to control the production of salt. It is astonishing how effectively Genoa and especially Venice managed to take control of production as well as trading. Genoa was positioned in the Western Mediterranean and Venice at the head of the Adriatic. Each used all its political and military strength to consolidate its local trade, and to encroach as far as possible on that of its rival. However, Venice was more organized politically, which translated into more ruthless and effective use of state power. And Venice made a conscious decision to concentrate on the salt trade, whereas to the Genoese it was just one of a set of potentially profitable cargoes. Where the two came into conflict over salt, the Venetians tended to win.

Venice managed to make a business out of control of the Adriatic salt trade. Venice owed some of its early wealth to the salt trade from salt works in its lagoon, and had a number of contracts with inland Italian cities in the 13th century to supply them with salt. The more that Venice came to control the salt trade in the Adriatic, the more the resulting profits were used by the city to subsidize other trading activities. Venetian traders delivering salt to the city were given bank credits, for example, allowing them to buy goods quickly. As the historian S. A. Adshead has written, "For the Venetians, salt was not a commodity among commodities... it greased the wheels of all the working parts and fuelled its motor". The salt trade allowed Venetian traders to compete very effectively with their rivals across the board. Salt was "il vero fondamento del nostro stato." Always, the Venetians were willing to exercise raw power to foster their control of salt.

The Roman salt-making center in the Adriatic was at Comacchio, a little north of Ravenna. After the fall of Rome, records of the 8th-century Lombard King Luitpold tell us that Comacchian salt was being shipped to all the major inland cities in Lombardy, through Ferrara at least as far as Parma, Lodi, and Brescia. However, Venice was producing salt by 523 AD.

The Venetians set out to dominate the salt trade. In 932 they destroyed Camacchio. They burned the citadel, massacred the inhabitants, and carried off the survivors to Venice, where they had to swear an oath of loyalty to the Doge before they were released. The Venetians began to construct salt works on their own lagoon, and around 1028, we find the Doge of Venice giving permission for Chioggia to build more salines on the Venetian lagoon. However, it turned out that it was not as easy to build salt works in the relatively exposed, storm-prone lagoon of Venice as it had been at Comacchio, and it took a long time before salt production became really successful at Chioggia. Meanwhile, the city of Cervia, south of Ravenna, filled the production vacuum left by the destruction of Comacchio. Cervia was in production at least by 965­975 AD.

Around 1180, it was clear that Cervia and Chioggia were rivals for salt production, under the protection of Ravenna and Venice respectively. The Archbishop of Ravenna and the Doge of Venice now began playing hardball. Venice declared it illegal to sell Chioggia salt to be sold or shipped without a Venetian certificate, and Ravenna did the same for Cervia. The salt market was now out of the hands of merchants and in the hands of the politicians. By 1234, war between Venice and Ravenna ended with a ban on any Ravenna (Cervia) salt being shipped northward, and Venetian galleys enforced the treaty.

Now the Venetians went one logical step further: for all practical purposes they gave up trying to be salt producers, and instead concentrated on being (monopoly) salt traders. Between 1250 and 1280, they came more and more to be the dominant buyers of salt, which they then shipped and sold. By the 1350s, no salt could move on a ship in the Adriatic unless it was a Venetian ship bound to or from Venice.

A golden rule of Venetian policy was that all trade goods under their control must pass through Venice. As late as 1590 they were making an 81% mark-up on salt sold inland, but that was not always the case. Sometimes Venice sold salt at less than normal rates if it would foster trade in higher-value goods that would yield more profit. All this activity was planned and supervised by a special State body, the Collegio del Sal. The rewards were staggering, and help to justify the tenacity and ruthlessness with which the Venetians operated the salt business. Typically, Venetian merchants bought salt for 1 ducat a ton, and it cost them about 3 ducats a ton to ship it to Venice. There they received a State subsidy of 8 ducats a ton. The State collected a tax as the salt left Venice, and after shipping to the customer, the selling price was roughly 33 ducats a ton. That was a profit worth fighting for! And it was not only the merchants who profited. Some of the State profits went to the architecture, sculpture, and paintings that remain today for our admiration.

The Venetians had different methods for maintaining their trading monopoly. On the island of Pag, they would buy up all the salt that was not needed locally. It would then be shipped to Venice and sold (at very high prices) to customers. At Muggia and Capodistria, the Venetians were given a fraction (about 10%) of the salt produced (presumably as protection money), but the locals were allowed to sell the other 90% only as long as it was carried overland, effectively limiting its value and the sales area.

As late as 1578, the Venetians destroyed the salt works at Trieste, and in the following twenty years were making an 80% profit on salt sold inland on the Lombardy plain. But around 1600, paradoxically with the defeat of the Turks at sea, shipping in the Adriatic became too great for the Venetians to be able to maintain their monopoly by force. Their source of riches in the spice trade had been cut off as the trade routes to India now passed around Africa, and their shipping was declining.

Page last updated May 1999.

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