SALT PRODUCTION  [and "secret salt' ]

Continuous and reliable supplies of Salt, were a matter of such importance that the establishment of early settlements, the rise and decay of civilisations, demographic shifts of populations and the development of agriculture, were intimately related to the immediate availability of salt.

The power to control a population's salt supply, was power over life and death.    Erratic sea level changes, particularly in the Mediterranean where the minimal tide was relied upon to fill coastal evaporation pans,  prevented some of these civilisations from obtaining consistent salt supplies, causing them to migrate or decay, conquor or succumb.

Boiling  [peat] - Solar pan evaporation - Rock mining - Saltpeter - Tinder - Gunpowder - The East India Company -Glass - Leather - table salt - 

Salt is physiologically absolutely necessary for human life, but in the past [prior to the Industrial Revolution] the known mineral salt sources were so limited  that its supply  was a critical demographic power factor for most communities.

   It was only available as visible and exposed rock outcrops in arid regions, or as dried out salt cake on the shores of some seas and salt lakes. In areas with wet climates, the protruding salt dissolved making it almost impossible to discover.    It is probably this, more than for any other reason, that many of the great civilisations first developed near deserts and desert climates, for example the Mediterranean region, at the edges of the "arid" zones.

Solar evaporation on vast flat coastal areas was considerably easier, than manually quarrying and hacking at rock salt. Though the technology was not easy and was handed down from generation to generation.   A large share of the world's consumption of salt - is still made by the ancient methods of trapping seawater or salt spring brines, and evaporating the brine and concentrating the salt, either artificially, or under the sun's heat.


U.S. salt production has become more efficient. At the time of the U.S. Civil War, 3,000 workers produced over 225,000 tons of salt in the United States. Today, there is a third more workers, but they produce 100 times more salt.

China has more than doubled its production in the last 10 years

Worldwide, salt production tracks consumption which, in turn, reflects population growth (food salt) and industrial development (chemical salt, salt for animal nutrition, roadway safety, water conditioning, etc. Salt production globally was about 250 million tons in 2006

 see Salt Institute statistics

Table Historic Salt production per man employed [known figures]
Period   Locality    		(tons)  Men employed  	Method ofProduction One man makes per year (tons)
 1900    Taodeni(Sahara)        		4000                  250               primitive mining                 16
 1900    Coserra(Italy)             		6000                  250               primitive mining                 24
 1890    Sicily                           		17,000              400                primitive mining                 43
 1660    Tirol(Austria)              	  	12,000       250 (+300 for gathering wood) brining    48 (22)
1700    Rhe’(France)              		4000                 250               solar                                   16
1960    Reichenhall(Germany)                                   100,000              400               brining                              250 


Ancient coastal salt manufacture depended on the availability of wide flat coastal areas and in making clever use of natural, shallow depressions, lagoons or manmade salterns about 15-20 cms deep. These had to be positioned at mid-tide level to facilitate filling [without industrial pumps], the evaporation pans in order to concentrate the brine, and later for harvesting and drying the precipitated crystallised salt.

  China circ. 400 ad drilling to over 2000 ft depth





  China - Drilling for salt circa 400 AD - to depths of 3000 feet" "Chinese salt pan production - still used today. 
Yellow River - the great bend.

Chinese technology included drilling into a salt deposit, with at least two holes one to feed and flood fresh water  into the salt diaper, and the second hole to allow the water to 'well' up after dissolving the salt, into the evaporation pans, where it could be again concentrated by evaporation. Evaporation would then occur either by solar heat, or by manual boiling using convenient fuel for burning.

CHITOWNRIGS.jpg (43159 bytes)     Chinese Town Drilling rigs and wells

It takes approximately, 50000 cubic/m of sea water spread over 100000 sq/m, of flat solar evaporation area, to produce 1000 tons of salt a year. There are two other important conditions:

  1. # an equable climate with a warm breeze and a hot sun
  2. # a reasonably steady sealevel. [The Mediterranean tide fluctuates only a few centimetres, whereas the oceans may have tides of more than than some metres]

Such areas were abundant when the sea was one or two metres below its present level; they became comparatively rare with a sea level of one or two metres higher, Even in Delta areas of the some rivers, like the Nile, Rhone, and the Euphrates, the establishment of new pond levels was very difficult, and the cycling of the brines from one level of concentration to the next could take months and years .A change of climate conditions, or a minor ocean fluctuation could have had a serious effect for ancient coastal saltmaking.  Manual rock mining or inland salt springs or lakes like the Dead Sea suddenly became the only alternative.

Fuel needed for production of 1 ton salt 
of fuel
Fuel Source of fueland salt Method used  Location  Year
4 wood brining and wood gathering on 100,000 sq/m woodland per year 'camp' fire Tyrol 1600
14 peat Ocean water Ash extraction Jutland 1650
6 coal Ocean water Open pan England East coast 1700
1 coal Brining Open pan Cheshire 1700
0.2 coal 20 kw/hr Vacuum pan Germany 1950
0.02 coal 200 kw/hr Vacuum pan - compression still Switzerland 1950
0 solar energy 100 sq/km of flat impermiable pan area at ocean tide level Solar pan Mediterranean  1950


Among other important concepts to move the huge quantities of brine, and technical innovations developed in producing salt, were the measurement of density and pumping by screw, both ascribed to Archimedes.       The first use of impellers and sail type windmills was to operate an Archimedean screw and chain pumps for controlling water and brine flows. To move the huge quantities brine from the sea into the evaporation pans, controlled flooding by tides was the only answer.


In regions where solar energy could not be used the salt maker was forced to use solid fuel to 'boil' brines. In northern Europe, [PEAT PRODUCTION OF SALT] - and also wood.    Whole forests were devoured leaving only the stumps. In Japan it was seaweed.

HALLE Germany - boiling pan model HALLE Germany - boiling pan model
hallemf.jpg (141337 bytes) dmusea.gif (4103 bytes)
Saltwell at Luneburg before 1500 Luneburg Salt well before 1500 - In 1569 the well was converted to a pumping system Up to the year 1569 the brine was won out of the "Sod" (well pit) with a barrel-like jar called "Öseammer". The workers of the salt works called "Sodeskumpane" had to lift up the jars with their own muscle power. A kind of seesaw called "Sodrute" served as a lever. When visitors come upstairs from the basement they stand in front of a faithful copy of such a "Sodrute" with a "Öseammer" hanging from it

Solar pan Evaporation

Crystallisation of salt in solar pans in hot climates, occurs naturally. The crystals first form on the surface of the brine. As they become soaked -  the evaporating surface brine reaches saturation point before the cooler lower layers.

  salt 'mushrooms' growing in the Dead Sea

Salt mushrooms growing in the Dead Sea - nucleation occurs

 quickly upon anything protruding from the brine

Additional crystals grow beside these crystals which become partially submerged, rather than below them, or above them, and a typical "funnel" or wedge shaped form of crystals takes shape. The familiar salt "mushrooms" can be seen growing in salt lagoons and pans.

     Manual harvesting in Moroccomoroccosaltpans

The specific gravity of a Sodium Chloride crystal is 2.16. and the saturated brine at 25 C contains 26.7% salt. and has a specific gravity of 1.2004. At 15 C a saturated solution contains 26.5% salt, and has a specific gravity 1.203. Hence a solution saturated at a higher temperature is specifically lighter, even though it contains a greater quantity of salt. It is this explanation that allowed salt makers to crystallise "blocks" or briquettes of salt on moroccopans2.JPG (20256 bytes) the surfaces of ponds, using floating elements such as sticks and straws to form the crusts of salt. . It should be noted that with most other substances, crystallisation can not occur at the the solution surface because their solubility increases more rapidly than their specific gravity decreases. [see Jewish Salt Technology - Religion]

Dikes enclosing solar evaporation ponds and pyramids of raked-up salt

 Dikes in solar evaporation ponds




At the end of the last Ice Age, around 17-15000 BC, the ice sheets covering the earth's surface began to retreat, flooding the continental shelf where many early populations seem to have lived. The average mean sea level rise was about 1 metre a century, the most rapid period being betwen 8,000 and 5,000 BC By about 2000 BC the oceans had recovered from the Ice Age lowlevel, risen again and had probably reached a metre or so above today's level.

Sea level variations, either seasonal, short lived or long term may have been caused by different events or a combination of them. Among the most obvious, may have been changes in atmospheric pressure, changes in ocean currents, wind driven waves, storm surges, heavy rainfall increasing the run-off from rivers.

However, as the last ice age has demonstrated, [and of present concern regarding global warming,] the colouring of Antarctica with Volcanic ash, or other pollutants and the subsequent warming fusion [fractioning] and melting, of the polar ice sheets and glaciers was, and is, of catastrophic proportion in comparison
Control of the colour of the Antarctic ice cap, and the ALBEDO of the white snow cap, may be our immediate concern in the near future. 


Many regions of the Earth, for instance equatorial Africa, consist of igneous rock where rain and ocean spray dust are the only sources of salt .  Plants exist which are capable of concentrating such dilute solutions by evapotranspiration, and there are insects which can collect salt from water containing less than 0.006% of chlorides and concentrate them in their bodies to about 0.3% . Until recently some humans survived solely by drinking the blood and urine of herded and wild animals. Roaming over wide areas these animals collected and concentrated the salt in theirhammercal1.gif (31095 bytes) blood by feeding on large quantities of plants . (Man tribes like the Masai kept their animals alive for systematic bleeding.) Springer's map of precolonial Africa shows immense areas where this happened and the low population density of the African

Typical Calcolithic hammer

hammercalcol.gif (140386 bytes)

hinterland can be ascribed to this diet of near salt-starvation . Furthermore, there is no doubt that early settlements grew up around salty springs which hunting tribes had discovered by following animals to their salt licks.

Another remarkable source of salt is registered in Springer's [110] map, namely where people burned plants to use the resulting ash as a supply of very poor grade salt; in effect they replaced the stomach of the ruminant animal by combustion.

Cardona's Salt Mountain CARDONA SALT MOUNTAIN - Spain

One might almost call it the first primitive agriculture. Shcultz a describes how "... in the Brazilian rain forest, deep in the Amazon river watershed, live the Suya people. Their women collect water hyacinth, dry them and burn their leaves. The ash is then passed through a kind of grass filter after it has been dispersed in hot water. The filtrate is evaporated in an earthenware pot over a wood fire until it becomes a thick brown sauce which jellies to a dirty coloured mass when cooled down . This, divided into minute portions, serves as spice..."

Although this ash is too rich in potassium carbonate to serve as a good source of salt, it is almost the only way to avoid salt starvation. The other alternative is cannibalism [19b]. As Springer points out, "It is known that salt-starved animals eat part of their litter in order to stay alive, and consequently several authors have ventured the opinion that extreme salt hunger is one of the causes of cannibalism. This seems to have become habitual in parts of Africa and New Guinea where people have been subject to serious salt deficiency for a long time..." Primitive man living in rain forests far from the sea suffer the same deprivation , as generally it is not practicable to transport ocean water, with its 97% water-content, deep inland. The aborigines in New Guinea, however "... make secret expeditions to the sea coast.... to put seawater into hollow bamboos which are carried back to their tribe.

There were many early attempts to quarry and mine salt. Salt tunnels containing stone hammers and axes have been found at sites in Asia Minor, Armenia, South America and near the salt river civilization in Arizona. The Hallstadt salt mines in the Austrian Alps and the Italian mines in Lungro, Cosenza and Etruscan Volterra supported prehistoric communities forming important centers of inland civilization. , Surprisingly, very similar specialized tools were used in all four continents. , , The production of salt from concentrated brine is much easier than quarrying or mining. The method consists essentially of bringing the natural brine into shallow ponds enclosed by low earth walls and allowing the Sun to evaporate the water. The deposited salt layers are then harvested. On the shores of the Dead Sea one may find disused solar pans that were dyked by ancient saltmakers. In China very old solar pans described in 1882 by the German geologist von Richthofen are still in operation at the saltwater swamps that lie in the great bend of the Yellow River. Operations similar to those described by von Richthofen provided salt for Iran's important Isfahan district. In Africa , Timbuctu and Kano were supplied for thousands of years from Taodeni and Bilma.

chiboil.gif (51563 bytes)

Salt brine boiling

A striking feature of salt swamps is the red colour caused by algae and bacteria multiplying in their stagnant water. The salt produced there is red, whereas quarried salt is grey and usually contains gypsum which gives it less flavour because of reduced solubility. The Madaba Map , dating from about 550 A.D. shows two ships sailing on the Dead Sea , one loaded with reddish salt from the old solar ponds and the other with grey salt from the quarry at Mt. Sodom.

The red brine not only looks like blood but also tastes like it and makes a deep and disturbing impression. The Bible indicates this in Kings II.3.22 "And they rose up early in the morning and the Sun shone upon the water, and the Moabites saw the water on the other side as red as blood. And they said, "This is blood".Dunaliella 'red' ponds

Airphoto of 'red' brines in static ponds coloured by 'Dunaliella' algae

This passage probably refers to the red salt pans at Sodom. The old name ";Sodom" for the southern end of the Dead Sea may be a contraction of the Hebrew words "sade" (meaning field) and "adom" (meaning red). That reddish salt was made there at the time of the Jewish uprising against Rome about 130 A.D. is proved by pieces of salt found by Yadin in a burial cave of the period . This salt corresponds in colour and size of crystal, to what would be expected from careful crystallization from red brine on sticks.

It was the Chinese who about 400 A.D. conceived the modern idea of drilling deep into salt deposits and bringing up the brine for evaporation. They used bamboo pipes and some borings were as deep as 1000 meters. As fuel for evaporation they used coal, wood or natural gas which came from the same wells .

 CHIGASBOIL01.jpg (27903 bytes)

 Maya Treasure: Empire's First Wooden Artifacts
The remnants of a large
salt factory are found submerged in a peat bog
off the coast of Belize.

By Thomas H. Maugh II, Times Staff Writer

A Louisiana archeologist has discovered the remains of a massive Maya
salt-production complex submerged in a lagoon off the southern coast of

Examination of the underwater site also revealed the first wooden
structural artifacts from the empire, including poles and beams used in
building the salt factories. A wooden paddle from the canoes used to
transport the salt via inland waterways also was discovered - the
first time such a Maya object has been found, researchers said.

Archeologist Heather McKillop of Louisiana State University reported
today in the Proceedings of the National Academy of Sciences that she
and her colleagues had so far discovered 45 facilities for salt
production in the mangrove peat bogs of Punta Ycacos Lagoon.

"There are many more sites there," she said in an interview.

The discoveries are "tremendously exciting," said archeologist Tom
Guderjan of Texas Christian University, who was not involved in the
research. "We have never, in that region of the world, found
preservation of architectural materials [wood] like she has found

The discovery of the paddle is particularly intriguing, he said,
because even though Maya art shows canoes, researchers have been unable
to find any traces of them.

"We've all been looking for the canoe," Guderjan said. "It could be six
inches under the muck."

Salt played a crucial role in ancient economies because humans needed
it to survive and also desired its taste. It also has a variety of
secondary uses, such as preserving food.

The cities of the Maya civilization are largely in areas that have
little salt. Researchers previously discovered ancient production
centers in the salt flats of the Yucatan as well as along the Caribbean
coast, but none is large enough to have accommodated the needs of Maya
society, which dominated much of Central America from approximately the
4th century to the 16th century.

McKillop's findings suggest that many, if not most, of the Maya salt
facilities were along the coast and became submerged during the last
millennium as ocean levels rose. The immersion actually led to their
preservation. Being buried in peat protects wood from decay, McKillop
said, and being underwater prevents artifacts from being trampled,
making identification and analysis much easier.

McKillop initially identified four salt production facilities in the
lagoon and decided to expand the search. A team of students equipped
with snorkeling gear divided the surface into grids and looked for
submerged pottery, buildings and other items.

In three weeks of study, they found 41 sites characterized by pottery,
wooden posts and beams, obsidian objects and other artifacts.

The largest structure was at Chak Sak Ha Nal, where 112 posts define
the exterior walls of a rectangular building measuring about 36 by 65
feet. Inside the perimeter are 31 posts marking off rooms. The
arrangement of the structure's other pieces of wood, such as beams,
remains to be mapped.

The interior areas contain remnants of large, apparently mass-produced
urns that sat over fires on clay cylinders about a foot high. Seawater
would have been placed in the urns, scientists say. The water would
boil away, leaving behind the salt.

Although it has just begun examining the sites, McKillop's team has
found extensive evidence of artifacts produced in inland cities,
indicating well-developed trade over the Central American waterways.
The salt would have been loaded into canoes and paddled upstream, where
it would be exchanged for a variety of goods.

The partially degraded paddle that was discovered - virtually
identical to those seen in Maya art - ties the salt facilities to
inland trade, McKillop said.

The facilities "represent a new kind of economy that we haven't looked
at before," she said. Researchers have long studied the royal court
workshops in large Maya cities that manufactured goods for the elite.
At the opposite end of the scale, they have studied household economies
where family members made things for their own use.

The salt factories represent an intermediate stage in which small
groups of people were producing things for the entire society, McKillop



Related Links | Activities | Email List

COPYRIGHT NOTICE AND DISCLAIMER © Copyright David Bloch, 1996. All rights reserved. Copying of this document in any material form is prohibited other than as necessary for the purpose of viewing on this Web site. The contents of this document is for general information only. Nothing in this document constitutes legal advice.  This web page and those derived from this page, gives collected information derived from other sources believed to be accurate at the time of storage on available Internet disk space.. These web pages are non commercial, and academic in purpose, and are stored as personnel information for the page owner's own use. No warranty of accuracy, reliability or completeness is given and (except in so far as liability under any statute can be excluded) no responsibility arising in any other way for errors and omissions or in negligence is accepted by the author and page owner, David Bloch MRBLOCH SALT ARCHIVE, in the event that others access these pages 

back to "SALT made the world go round"