The Salt Pans of Samut Sakhon

Samut Sakhon lies on the northern shore of the Gulf of Thailand, at the mouth of the Tha Chin river to the west of the Chao Phraya, on flat, low coast where the tide reaches far inland. Along this coast and its neighbours, Samut Songkhram and Phetchaburi, sea salt has been made by evaporating seawater in shallow earthen fields, and it is the salt of the central Thai kitchen.

Sea salt is the oldest seasoning of the Thai table, and the salt fields of the Gulf coast are where much of it is made. Seawater is let in on the tide through channels and held in a series of shallow, levelled pans, each beaten flat and hard so that the brine does not seep away. The sun and the wind do the work; as the water shrinks the brine passes from pan to pan, growing stronger, until salt crystallises on the floor of the last and is raked into heaps to drain. The salt is made in the dry season, when the sky is clear and the evaporation is quickest, and the rains bring the work to a halt. Thompson places salt among the foundations of the Thai kitchen, and the reason is plain from the cooking itself. Before fish sauce, shrimp paste and soy were bought in bottles and jars, salt was what preserved the catch of the Gulf and the rivers. Salted and fermented fish, shrimp paste (kapi) made from small shrimp pounded with salt and dried, and the brine-cured foods of the central plain all begin with it. Fish sauce (nam pla), the seasoning that stands in place of salt in so many Thai dishes, is itself nothing more than fish and salt left to ferment. The saltiness in a Thai curry, a relish or a dipping sauce therefore leads back, step by step, to the pans of the coast. The salt is also used directly, and in ways that depend on its character. A coarse, slightly damp sea salt, grey or off-white and carrying the bitterness of the minerals that remain in it, is not the same thing as a refined and dry table salt, and the cook who knows the difference seasons accordingly. It is used to cure fish and eggs, to draw water from vegetables and fruit, to pack in pickles, and to coat a whole fish before it is grilled. Salt crust cooking, in which a fish is buried in salt and baked or grilled, belongs naturally to a coast that has so much of it. The country around the pans is low and open, laid out in rectangles of earth, water and white heaps, with the shrimp and fish of the Gulf close by. That proximity matters: the salt, the catch and the preserves made from them come from one stretch of shore, and the cooking of the central plain draws on all three. Samut Sakhon is among the great fishing and fish-processing districts of the Gulf, and its salt belongs to the same economy of the sea as its shrimp and its fish sauce.

The salt of the Gulf coast gives the Thai table its first taste, and Thompson treats saltiness as one of the balanced elements of a dish rather than a flat seasoning. It reaches the plate chiefly through fish sauce, shrimp paste and cured fish, each of which adds savour as well as salinity to curries, relishes and dips. Used directly, a coarse sea salt gives a rounder and more mineral salinity than refined salt, and it is the salt of choice for curing, pickling and crusting.