The production process of the balsamic vinegar was first described in a letter from the 19th century written by one of the most famous balsamic vinegar producers. The same production process is used today and is part of the standards written by the Balsamic Vinegar Consortium.
There are two types of PDO traditional balsamic vinegars (aceto balsamico tradizionale DOP): the one from Modena, the most famous, and the one from Reggio Emilia, not as known but with an equally good quality.
To obtain the traditional balsamic vinegar PDO there is only one ingredient: the must of grapes from the region. The must is cooked for at least 30min to no less than 80°C. After that it is left to age for at least 12 months.
It is also known as aged balsamic vinegar because it is left to ferment in specially designed wooden barrels for 12, 25 years or more. The result is a dense, sweet, low acidity brown liquid that is much appreciated in the gastronomic cuisine.
The balsamic vinegar PGI (aceto balsamico di Modena IGP) contains three ingredients: grape must, a small percentage of wine vinegar, and around 12% caramel.
We will be referring to the traditional balsamic vinegar PDO (aceto balsamico tradizionale DOP) in what follows.