aged balsamic vinegar

Balsamic vinegar (Italian: aceto balsamico) is a traditional flavoured vinegar commonly used in Italian cuisine. It is also often used as a salad dressing when combined with oil. It is a traditional product originating in Modena, where it has been made since the Middle Ages and some of the denominations (notably: "Aceto Balsamico Tradizionale di Modena") are protected by the European Union. Unlike common vinegars, it is dark and thick with a complex, sweet taste and is much more expensive.

In its long-aged forms (at least 10 and even up to 25 years) it is often taken straight or served over strawberries, while the more mass-market vinegar (usually aged 3 years or less) is used in salad dressings and marinades. Balsamic vinegar does not deteriorate after opening as oxygen.

It is produced from the concentrated juice ("must") of white grapes (typically, trebbiano grapes) that has been boiled down to approximately 50% of its original volume, and fermenting that with a slow aging process that concentrates the flavours. The flavour is intensified over decades, with the vinegar being kept in fine wooden casks, becoming sweet, viscous and very concentrated in flavour. The finest and most traditional balsamic vinegar is very labor-intensive to produce; while it ages and gradually evaporates, the liquid is transferred to successively smaller casks made of different woods, absorbing the flavor characteristics of each wood and becoming more concentrated with each transfer. Oak, mulberry, chestnut, cherry, juniper, ash, and acacia are the most commonly used woods. Some older balsamic vinegar is added to the "must" to create a more complex and intricate taste, and to add acidity. from Modena, Italy Types of Balsamic Vinegar.