Produced in Modena, Italy, it is sold under a label of authenticity making it superior to cheaper factory-produced balsamic that often has added caramel to enhance colour and taste. The must of late-harvested white Trebbiano grapes is boiled until reduced by half and then transferred to, and aged in, wooden casks. During the hot summer months the balsamic evaporates and concentrates and in the colder months it rests and matures. As it ages, it is siphoned from barrel to barrel of decreasing size and different woods, which add a variety of aromas to the vinegar. Ageing can take up to 10 years and as long as 50 years. As it ages it becomes richer, sweeter, syrupy and more expensive. It is used in both sweet and savoury dishes and the older vinegars should be used very sparingly. The sweetness makes it ideal to dress bitter salad leaves such as radicchio and chicory or fresh fruits such as strawberries and figs.