Nigari is distilled seawater with the salt removed. It was used as a coagulant for tofu, but these days calcium sulfate is more commonly used, just as salt comes mostly in the refined form of sodium chloride. As such nigari’s role in our diet has faded, but in fact nigari has more than a hundred minerals in abundance, including magnesium chloride. The mineral balance of the sea is almost the same as that of humans, making nigari very important for us. Natural nigari, particularly in liquid form, is absorbed much easier by the human body than synthetically made nigari.