Periwinkles — winkles — are small edible sea snails plucked by the handful from cold rocky shores, where they graze the weed-covered rocks of the intertidal zone. Each is a small, blunt-spired spiral shell of dark grey to near-black, sealing a coil of firm, grey-brown meat. Boiled in seawater and teased out with a pin, the morsel eats chewy and resilient, intensely briny and clean with a faint mineral, almost iron-like tang of the sea. A humble shore food of the British Isles, Ireland and West Africa, the common winkle, Littorina littorea, is what most of the North Atlantic means by the word.