We were in Brittany a few weeks ago, and visited the salt fields of Guérande. There were no paludiers in evidence, only acres of neatly tended salt ponds. Guérande salt comes in two kinds — one grey and very moist, and the other the brittle, pinkish fleur de sel (‘the caviar of salt’), which is ludicrously expensive if you don’t buy it at source. Or you can make it yourself: the following directions, quoted in Salt. A World History, are from Cato’s De Agricultura: Fill a broken-necked amphora with clean water, place in the sun. Suspend in it a strainer …