Grey sea salt (sometimes called Celtic sea salt) is a slightly moist, unrefined sea salt produced in the coastal regions of France. It is harvested from the Atlantic Ocean by hand using wooden rakes in the traditional Celtic method. It has a light grey, almost blueish colour and a complex flavour due to the presence of small amounts of clay and minerals that it naturally retains from the sea water.
Grey sea salt is becoming a popular finishing salt for dishes of all kinds, including sweets. It’s not uncommon to find it paired with chocolate and caramel in fancy dessert cafés.