Fleur de sel, literally “flower of salt”, is a high-end French sea salt and is considered by many to be the creme de la creme of salts (to borrow a phrase from the French). It is traditionally used as a finishing salt–meaning that you don’t cook with it, but sprinkle it on food just before eating.
In some French households, it is not uncommon to see a small container like the one pictured placed table-side to garnish meats and vegetables with a light pinch immediately before eating. We have used it on steak (no/less presalting of meat before cooking), on French fries, oven fries, potato chips, and even simply on steamed vegetables.
Characteristics of fleur de sel
The smaller, finer crystals compared to regular sea salt allow the grains dissolve rapidly. The flavor is more delicate than table salt, contributing other minerals and tastes to the dish. Colors range from white to light pink, but is most commonly a light grey/off-white color. (Pink salts are colored by the algae Dunaliella salina, and can contribute a subtle violet flavor.)
The culinary applications are not the only thing that drives high cost for the salt. The difficult, labor intensive, and short harvest period from mid-July to mid-August also ensures that the supply is fairly low. Yields from the salt marshes vary, but per season, a single marsh produces about 60 pounds of fleur de sel compared to the 2,200 pounds of “gros sel”, aka regular sea salt. (Basically, for every 40 pounds of regular salt, you get one pound of fleur de sel!)
The salt itself commonly forms at night as the cold ocean air flows over the warmer, shallow salt marshes. Fine crystals form on the surface, allowing the saliculteurs to gather it before it sinks. The term for the saliculteurs changes by region, in Guérande they are known as paludiers, but in Ré and Noirmoutier they are known as sauniers.
The saliculteurs literally harvest the thin layer of fine crystals from the surface. They gently pull a paddle, called a lousse, across the surface to gently gather the salt without making it sink.
The fleur de sel from Guérande (in the Breton region) is considered by many to be one of the more respected varieties. Other notable French salts come from are Noirmoutier, Ré, and Camargue.
(Fortunately for me, I have family near Guérande so I always get to bring some salt back to the US when I visit!)
and knowledge from my trips there.