Red herring is a famous export product from East Anglia. The method of preserving the herring was to soak it in brine of salt and salpeter and then smoke it over oak and turf. The story is that this technique was discovered by a Yarmouth fisherman who had an unusual large catch. He hung the surplus herrring is a room with a particularly smokey fire. The next day he noticed that the white flesh of the herring became red.