Where does red salt come from - and where can I buy it

A. Alaea red salt is unprocessed, mineral-rich sea salt from Hawaii, which is mixed with local red clay. In the late 18th century, Captain James Cook reported that the Hawaiians made excellent salt, but he complained that on the island of Atooi, today known as Kauai, the salt was brown and dirty. This was caused by mixing the salt with local volcanic red clay, alaea, which is brick red because of the high iron content. The salt was made for ritual blessings and religious feasts, and today it's much sought-after by chefs and food critics. At present, it's only available in the States, but you can order it online at www.cmccompany.com or at www.globalfoodmarket.com

Q. What other types of specialist salts are becoming popular

A. Grey salts, black salts, and salt with visible impurities will be the big trend of 2002, according to food writers. Many consumers distrust modern factory salts and would rather have a little mud than iodine, magnesium carbonate or calcium silicate. But there's no evidence such chemicals are harmful, and some manufacturers are considering adding fluroide to salt for its benefits.

One of the most popular salts is black salt (kala namak), which is an Indian brown/black salt, which turns pinky when crumbled and smells sulphurously smoky.

It's much used in Indian dishes such as chaat, a spicy fruit salad. You can buy is from Curry Direct, www.curry.direct.dial.pipex.com

Fleur de sel - this is pure white salt crystal flakes from Brittany, the highest quality salt you can buy. It comes from the crystals formed on the surface of the salt pans, which have never been coloured by the clays on the bottom. It costs around 5 for 250g - available from Villandry, Great Portland Street, London. (020 7631 3131).

Le Guerandais gros Sel Marin is coarse sea salt from Brittany, on sale in Sainsbury's Special Selection.

Maldon Crystal Salt is natural, pyramid-shaped sea salt crystals from the Essex marshes, available in most supermarkets and healthfood shops.

Q. Where do most grey salts come from

A. The old-time producers in the Bay of Bourgneuf in France are enjoying a revival of their tradition. These were the salts that Jean-Baptiste Colbert, commerce adviser to Louis XIV, had complained could be so much more sellable if they were whiter. The problem with the Bay of Bourgneuf salt was the dark umber clay at the bottom of the ponds. Particles got caught in the square sodium crystals. Colbert was wrong. Today consumers will pay very high prices for the grey salt of Guerande, Noirmoutier or Ile de Re.

Many French traditions vanished during the 1980s, including kigsall, the salted pork of Guerande. In Noirmoutier, the salt business almost died between 1986 and 1994, but traditional salt-making has flourished over recent months.

Q. What's the most expensive salt

A. The paludiers of Guerande (the salt-makers) command high prices for their salt because it is handmade and traditional. They make two kinds of salt, grey salt and fleur de sel. The light, brittle fleur de sel crystals are 10 times more expensive than the costly grey salt. French salt-makers do battle over what is true fleur de sel.

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By Katharine MacColl