Made from the white Trebbianno grape, balsamic vinegar gets its pungent sweetness from aging for several years in wood barrels. During the Middle Ages, this sugar-rich grape was used primarily for wine, but its high acidity made it better suited for producing vinegar. Produced in Modena, Italy, the maturation process takes place in a series of barrels made from a variety of woods and lasts from 6 to 25 years. Use it to dress salads and enrich stews, soups and sauces. Store in a cool, dark cupboard. Seek out aged balsamic and beware of inexpensive bottles - it may be a colored red wine vinegar with only a drop or two of 6 year-old balsamic added to it.