The main ingredient used to make tofu is soybeans. Tofu, also known as bean curd, is produced through a process that involves soaking and grinding soybeans, boiling the mixture, and then coagulating it with a coagulant like magnesium chloride or calcium sulfate. This results in a curd that is pressed into blocks of varying firmness, ranging from silken to extra firm, depending on the water content retained. Tofu is a popular source of protein, especially in vegetarian and vegan diets, and is versatile in cooking, easily absorbing flavors from spices and marinades.