Sweet mustard is a variety of mustard which is made from mustard seeds, vinegar and spices, but which has a softer and lighter flavor than the old -fashioned mustard. It is known for its sweet and spicy flavor, and for its smooth and creamy texture. Sweet mustard is rich in protein, dietary fiber and minerals, in particular calcium, iron and potassium. It is also a source of vitamins in group B, in particular vitamin B9.