Fleur de Sel (French for "Flower of Salt") is one of the most expensive salts available and widely considered to be the best. Sea salts gathered in a few different temperate costal areas which are mostly in France go by the name of Fleur de Sel, but the best and most widely recognized Fleur de Sel comes from a village in Brittany called Guerande. The salt is harvested by hand off the marshes and low lying areas which form salt fields in the months of July and August.

Fleur de Sel is a very specific kind of sea salt. The salt farmers in Guerande allow long and narrow shallow pools and marshes along the coast to fill with fresh salt water. Salt crystals form on the surface of the salt water as the water evaporates and the salt comes out of solution. Even a slight breeze sinks the salt crystals and the minerals in the clay at the bottom of the water give the crystals a grey color and these crystals make a very distinctive kind of salt known as Sel Gris (Grey Salt). On clear summer days such as those found in July and August in this very mild area of Brittany, there is no breeze and the crystals stay on top of the water. They are harvested with rakes which skim the salt off the surface and this is Fleur de Sel. For every 80 pounds of Sel Gris that are harvested only one pound of Fleur de Sel is yielded. This gives it a sticker price of over 100 times the cost of table salt, from $25 to $40 a pound.

Plain table salt is generally almost entirely sodium chloride, while sea salts contain a higher percentage of other minerals from the evaporating sea water which give various sea salts distinctive flavors. The crystals are also somewhat larger and coarser than the iodized table salt you buy in the grocery store. Fleur de Sel's irregular crystals form flake like clumps due to moisture (as would every day table salt without iodine) which makes it fairly crunchy. The amount of other minerals cuts down on the salt taste in Fleur de Sel and according to some it has an aroma similar to violets. The harvesting process ensures that Fleur de Sel contains only the purest part of the saline which also cuts down on the salty taste. What makes the salt from Guerande so special is that the area has a particularly mild climate, natural salt fields and particularly clean water currents from the Atlantic that makes the salt there superior to all other European salts.

Obviously this isn't reasonably priced to use as everyday cooking salt, which is fine since once the salt dissolves into a dish the subtle differences in flavor are hard to detect. Common uses are to garnish a nice dish, sprinkle onto bread with unsalted butter or as a spice to sprinkle onto a finished dish. I've had it as a flavor as part of a sampler to enjoy with a small slice of duck liver pate. Most gourmet stores will sell it in small portions and all you really need is a pinch at a time, which makes the price comparable to some exotic spices. Be wary of very discounted prices as they may not be for the real thing.