Any well-stocked kitchen is certain to have a bottle of balsamic vinegar straight from Modena, Italy. Or is it? If you bought it in a bottle bigger than a few milliliters, it's unlikely to be the real thing. Most of the stuff sold in supermarkets is nothing more than red wine vinegar with caramel coloring and flavoring—even if it purports to be "di Modena."
Traditional balsamic vinegar of Modena (aceto balsamico tradizionale di Modena) is rare and expensive, starting at about €400 a liter. It has only one ingredient: the "must," or residue, from cooked grapes, mostly grown within 30 km of Modena. The must is divided among barrels made from different woods—balsam, cedar, chestnut, oak, juniper or cherry— and ages for a minimum of 12 years.
The barrels are tipped periodically to absorb the essence of the wood. When the contents are aged, producers blend bits from each barrel as if they were concocting a potion, then allow that mixture to age for another six months. Professional vinegar sommeliers from Modena's regulating consortium taste the product to certify that it meets the standards. Only then can it be bottled in a specially shaped container, labeled and sold.
Most of the traditional producers of balsamic vinegar sell their vinegars on site and offer free tastings and tours of their vinegarias. Visitors to Acetaia Malpighi can follow production from cooking the grapes to smelling the vinegar rooms, followed by a free vertical tasting (www.acetaiamalpighi.it).
Villa San Donnino, offers tours and tastings along with accommodations at the villa (www.villasandonnino.it).
Check with the Modena consortium to find out if your balsamic vinegar is the real thing: www.acetobalsamicotradizionale.it.