The marsh was the first refinery.
Seawater is about 3.5 per cent salt, which is a poor place to start. The people working this coast in the Bronze and Iron Ages improved on it before they lit anything. Over three hundred red hills have been identified, mostly along the Essex and Norfolk coasts, with others in Suffolk and Kent; in Essex they cluster around the Dengie peninsula and Maldon, and around the Blackwater and Colne estuaries.
Archaeologists accepted the link to salt long before anyone could say what the mounds were actually made of. Excavation at Stanford Wharf, on the Essex bank of the Thames, settled it: fuel ash from burnt saltmarsh plants, harvested with the marsh sediment still adhering. Sea rush, sea plantain, sea lavender and thrift take up and hold salt as they grow. Burn them and the ash is saline.
Stir that ash back into seawater and the brine gets stronger. Essex helps too: around 600 millimetres of rain a year, in the shadow of the western uplands that strip the Atlantic air before it arrives. Brine that is not being rained on concentrates cheaply.
Rome, and something sour.
The Iron Age method survived the conquest and ran on into the fourth century. From about AD 250 the Stanford Wharf site was reorganised around four salterns, and traces of lead in two of them turned lead evaporating pans in Essex from conjecture into evidence. In a late Roman ditch on the same site lay a mass of tiny fish bones — juvenile herring, sprat and smelt — dumped in quantities that indicate fish sauce, liquamen or allec, made beside the salt that preserved it.
Nowhere else in Britain is the association with a salt-works so clear. Earlier in the Roman period a timber structure with an apsidal end had stood at the edge of the palaeochannel, probably a boathouse.
Salt and a sharp fermented liquid, produced together on Essex mud, eighteen centuries ago. It was not cider vinegar. It was the same idea.
Salt on one estuary since the Iron Age, with a gap in the middle that nobody mentions.
The year Essex had one salt-maker.
Little Domesday, compiled in 1086, records salt-houses along the Blackwater; Goldhanger and Heybridge are two of some twenty, and Hugh de Montfort held one and a half salina at Goldhanger. A knight paid rent to Henry III for the Goldhanger works in the 1260s. A guild of saltmakers was thriving across Essex by the 1390s.
Then the state noticed. Salt duty was reinstated in 1693, doubled in 1696, and collected by more than six hundred officials; by 1805 it stood at thirty pounds a ton. It was abolished in 1825, too late.
The Goldhanger works were abandoned around 1810, and by 1825 the Heybridge works had become a mill and maltings. Records for 1833 show a single salt-maker in the whole of Essex. What exists now took its name in 1882, when a firm whose main trade was coal put that name on the salt.
The pyramid and the apple.
The crystal is a hopper. Growth runs faster along the edges of a cube than across its faces, so the faces fall behind and the crystal builds outward as a hollow stepped pyramid. Halite does this.
The result is a flake: thin, light, all surface, quick to dissolve and read as saltier than it has any right to be. There is no cider vinegar tradition at Maldon and it would be easy to invent one. England's sour was malt, first known as alegar, and much of what gets shaken over chips in Britain is legally not vinegar at all: non-brewed condiment is water, acetic acid, flavouring and caramel colour. Cider vinegar was in print by 1810, in a cookbook that set it beside gooseberry and raisin.
The nearest long-documented orchard is at Aspall in Suffolk, about forty miles to the north-east, planted in 1728 by the Chevalliers with apple trees from their native Jersey. That is another county and a cyder house rather than a chip shop. The honest version is that the vinegar here is a modern choice.
