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The origins of salt
The Guérande marshes are a patchwork of ponds of varying geometric shapes, whose structure has been formed by the history and topography of the soil. The salt works is a production unit, a place where the salt worker works.
Follow the water to see how it works!
With a salt concentration of around 25 g/l, the Atlantic Ocean flows into the Croisic Straits, then along a system of channels, the “étiers”, right to the heart of the Guérande basin several miles from the ocean.
As soon as water is needed, the salt marsh worker opens the hatch during high tides and lets the seawater flood the “vasière” which is the first evaporation zone in the circuit that serves as a reserve between two tides. It also serves as a decantation zone, where suspended particles, mixed together by the sea, will settle.
A slight, constant change in level allows the water to flow into the evaporation ponds (the “cobier”, “fares” and “adernes”), which act as a daily reserve, supplying the final set of ponds - the “œillets”- from which the salt is harvested.
In the “oeillet”, the water reaches high enough concentration levels for the salt to crystallise (between 250 and 280 g/l).
The salt marsh worker's work and technique consists in carefully balancing water levels in the different basins in order to compensate for the water that evaporates every day. Thanks to this constant vigilance, the result of his work can be harvested: the famous Le Guérandais salt.