The first royal charter for the manufacture of salt was given by King David I in the 12th Century to Prestonpans. Salt was produced shortly after at Grangepans until 1889-90. It took 100 tons of water and 50 tons of coal to produce 3 tons of salt: in later years rock salt was added, imported from Liverpool and Carrickfergus, to improve the yield.

During the 16th and 17th Centuries both sides of the Forth were dotted with salt pans the product of which was mainly for export to the extent that on the 13th October 1573 the lieges complained to the Council, which prohibited the export of salt for three years. The panmasters complained that they could not live without the export trade and an agreement was made that they should supply the natives with what salt they required at an agreed price of 8s. the boll. At this time local pans included: Kinneil pans (or the Duke's pans), situated in the vicinity of Corbiehall Graveyard, where the slaughter-house stood in the early part of the 20th century; Grange pans, which were the pans connected with Grange Estate; Bonhard pans, connected with the Bonhard Estate, but situated on Carriden shore; Caris pans, which eventually became the pans of Carriden Estate situated a few hundred yards to the east of Burnfoot.

On the death of Sir Henry Seton in 1803, the Collector of Taxes, Cadell took possession of his dwelling place, Grange House. Salt production was still a major industry in Grangepans, but it was said that the seawater was "too fresh" and rock salt, imported from Liverpool and Carrickfergus, was added to strengthen the Grange salt: previously 100 tons of water would only yield 3 tons of salt. The salt was regarded as being of the highest quality and at 11s. per half cwt people came from far and near, a ton was carted to Falkirk every week to supply the inhabitants at a cost of £22 per cart or £1,232 per annum.

Nevertheless the demand for salt since the Agrarian Revolution in the mid 18th Century began to decline. This was because winter fodder such as turnips and mangel-wurzel were now available, and no longer was the majority of animals slaughtered in the autumn, and the meat pickled or salted, as fresh meat was now available all year round.

However cheaper Rock Salt from Cheshire was also being imported and the local stronger flavoured sea salt manufacturers couldn't compete on price, hence the last of the Bo'ness Grange pans, owned by the Cadell family, extinguished its fire in 1889. Salt however was still produced on the Forth, as non-edible salt, at Prestonpans into the 1950's.

Salt Manufacturing Process
Before steam pumps were available brine (seawater) was transferred from the River Forth at high tide using "wand" pumps to reservoirs, or more correctly settling ponds, where silt and other debris would be allowed to settle in this first stage of the manufacture and purification of salt. These pumps which were like giant seesaws had a bucket on the end which would be dipped into the Forth and filled with brine.

Once full the women and children operators would pivot the bucket round and empty it into one of the reservoirs to settle. Several days later when the water had settled the process was once again repeated, but this time emptying the brine into a large saltpan.

The massive saltpans which were rectangular (some measuring over 20ft long by 12ft wide) sat on stone pillars to allow space for the fire to burn under the entire area of the pan. "Panwood", which was actually inferior quality coal dross which could not otherwise be sold, was used to fuel the fire. Once the brine was simmering buckets of evil smelling animal blood, obtained from the local slaughterhouse, was added to the simmering brine.

Although a thoroughly disgusting liquid the albumen in the blood acted as a coagulant in the same way that a white of an egg can be used to clear wine. Thus when the albumen in the blood thickened and congealed it formed a scum that floated to the surface with all the impurities and was then scraped off using wooden rakes.

When the water all evaporated the salt crystals were removed using wooden shovels to prevent damage to the steel pans. Prior to the addition of Rock Salt this method could only yield a maximum of 3% salt as this is the normal percentage of salt in North Sea brine.

Sabbath Salt was produced on Mondays from the previous Saturday's brew, because the workers were not allowed to work on Sundays. As a result Sabbath Salt was a larger crystal of salt since the brine was allowed twice the time to evaporate, and naturally it sold for a higher price, which would help compensate the Panmasters for the lack of production on Sundays.