Prepared mustard is made by grinding mustard seeds and then combining the powdered, cracked or bruised form of the seed with an acidic liquid base such as vinegar, wine or water. This process occurs regularly in food-processing plants, but individuals can make prepared mustard in a home kitchen.
Mustard is traditionally made with either white, brown or black mustard seeds. Typical yellow mustard is made from the white mustard seed, which has a bold, piquant flavor. Brown and black mustard varieties are usually more coarsely ground than yellow mustard varieties. Mustard made from brown and black mustard seeds is typically spicier than that made from white seeds, but most truly spicy mustards have been combined with other spices, such as Chile powder. Mustard varieties are created when the mustard's liquid base is altered or when alternative combinations of powdered seeds and spices are used.
Mustard may be purchased in powdered form, in which case cooks have the option of getting creative by adding signature bases to create a unique prepared mustard. Sugar, cinnamon, black pepper and many other household spices can contribute to homemade mustard. Cooks should mix the powdered seeds and a liquid base to the desired consistency before letting the mixture stand for 10 minutes.
Mustard is low in calories; a teaspoon of yellow mustard contains 5 calories and 0.2 grams of fat. Mustard also provides traces of omega-3 fatty acids and selenium.