Tomato paste, available in a tube, is a convenient way to use a small amount. Store the rest of the tube, tightly covered, in the refrigerator for up to a year. If you use a can of tomato paste, freeze the rest in 1-tablespoon portions; add a frozen amount to a soup, stew or chili without thawing it first. Be sure to seal the tomato paste in an air-tight container, label and date it.