Modena's best shop for balsamic vinegar represents 20 or so DOP producers belonging to the strictest and biggest of the three consortiums affiliated with Modena's most famous product. Carry-on-friendly 100ml bottles – designed by famed automobile designer Giorgetto Giugiaro – cost between €50 and €150. Prepare to taste a few before committing.
Professional tip: stop by one of the gelaterias on Piazza Mazzini and pick up a serving of fior di latte (sweetened cream) or crema (egg custard) gelato and pair your tasting with that. You're welcome.