Modena is by no means the most historic or stunningly beautiful of Italian cities. Yet its claims to fame draw opera lovers and gastronomes by the thousands. Modena, you see, is the birthplace of two of the country's most glorious exports - Luciano Pavarotti and aceto balsamico. Locals actually sip small glasses of their heady brownish vinegar as an after-dinner drink. This novel custom has not yet reached our shores. But we have taken to dousing our greens with it liberally, combining it with olive oil and drizzling it over mozzarella, basil and tomato salads, adding it to piquant dipping sauces and, in my case, using it to jolt a gazpacho into new heights of culinary excellence. But, with the speed at which foreign food customs become internationally acceptable these days, who knows? Any day you might find yourself ordering a glass of fine aged balsamico to go with your strawberry tart. Wait a minute, this column is supposed to be about wine, not food. But you must remember that the word 'vinegar' comes from the French vinaigre, which translated, means sour grapes - in the literal sense. For years, clear vinegar served us nicely. Then, suddenly, we all switched to the tastier cider vinegar. During the 1980s, if you didn't pour a designer vinegar, laced with ginger, raspberry or thyme, you were simply not up on things gastronomic. Today even my aunt in Cleveland knows to stock her pantry with the pricey-but-oh-so-worth-it imported balsamico. Made from the unfermented juice of white trebbiano grapes, the liquid is boiled, then aged - for at least six, often more than 50 and even up to a staggering 100 years - in barrels made of any of a variety of fragrant woods, such as chestnut, cherry, ash and mulberry. The length of the boiling process, the years of ageing, the type of wooden cask, all play an important role in the finished product. This is why balsamic vinegars run the gamut in intensity, consistency, flavour, aroma and, therefore, price. I suggest you start with Modena's least expensive and work your way up. For some it can be a bit of an acquired taste, such as learning to like retsina, appreciating the differences, in ports or adjusting your taste-buds to the subtleties of cheeses. But most experimenters - once they begin to substitute balsamic for ordinary vinegar - never look back.