Black salt is a unique product from the Kostroma region of Russia (northeast of Mosow). It has dark gray crystals and a unique bread-like smell. Each family has its own particular recipe, mixing ordinary coarse rock salt with eggs, flour or the grounds of rye kvass (residue remaining from cooking kvass, a traditional Russian drink) or rye bread, cabbage leaves or sauerkraut. Sometimes the white salt is mixed with aromatic herbs like thyme and marjoram. The mixture is put into a linen tissue and baked in Russian oven atop a piece of birch wood. The oven temperature is typically extremely hot, up to 600°?, allowing the mixture to melt and turn in a solid lump. The ovens are closed while burning, and the salt bricks are left in the oven for 5-8 hours to burn the wood completely and allow the pieces of coal to cool down. The now-black salt brick is then ground and sieved, the excessive ashes are thrown away and the crystals of the black salt remain. Studies on the chemical composition of black salt have found that white salt under high temperature changes its chemical composition. The ash of the rye flour enriches it with minerals, particularly calcium, magnesium, iron and especially potassium. The black salt changes its physical characteristics as well, becoming looser and more resistant to the humidity. Black salt dates back to the 14th century, when the Holy Trinity Monastery (the largest male monastery in the area) placed its salt laboratories in the north of the country near Kostroma. For many years, Russian people used the black salt and passed the tradition of its production from generation to generation. Traditionally, the salt was prepared on Holy Thursday (the Thursday before the Easter) to garnish the Easter cake and eggs. Nowadays the black salt can be used as normal salt while cooking and as condiment. The only usage that is discouraged is in soups, as the blackening process makes part of the salt insoluble. With arrival of industrially produced, easily accessible salt and the persecution of the religion connected to the production of black salt, production had ceased so that over the years the methods and the recipe details were lost. In the distant villages of Kostroma, the elderly generation preserved the knowledge and the technique of making black salt is being revived. Nowadays, the salt is produced for home consumption by families in the Kostroma region and by a group of producers in the district of Kaduysk, in the village of Ivankovo, for the local market. In families, the salt is produced once a year for Easter (in quantities of approximately 1-2 kg per family). Since the formation of the group of producers in 2000, the maximum annual production was 12 tons. The producers’ group has created a company to distribute the black salt at the local market and through online shops.