It is pretty easy to determine the basic differences between balsamic and wine vinegar: Balsamic is darker, sweeter, and thicker than red wine vinegar. What gets a bit tricky is distinguishing one type of balsamic from another. While there are many different types of balsamic vinegars, they basically boil down (pardon the pun) to three varieties, which form a sort of quality pyramid.
VarietiesAt the bottom of the pyramid is the commercial version, labeled simply balsamic vinegar” or “aceto balsamico.” This a mass-market product based on wine vinegar with coloring, thickening agents, and flavoring added to it to simulate the flavor and consistency of a traditional balsamic vinegar. This is the least expensive of the balsamic vinegars (though usually a bit more expensive than most red wine vinegars) and the most familiar one to people outside of Italy. In fact, it does not even have to be made in Italy.
At the top of the pyramid is the original balsamic vinegar known as Aceto Balsamico Tradizionale di Modena (or Reggio Emilia)The next level up is Aceto Balsamico di Modena IGP (protected geographical indication). These vinegars must be made in the area of Modena and consist of a minimum of 10 percent concentrated grape juice, minimum 10 percent wine vinegar, and two percent caramel. An unspecified amount of older (10 years or more) vinegar may be added, and the must may come from seven approved grape varieties. At the top of the pyramid is the original balsamic vinegar known as Aceto Balsamico Tradizionale di Modena (or Reggio Emilia), made using the long and complicated traditional method. This product carries a DOP (protected appellation of origin) qualification, meaning that it must follow strict regulations and adhere to the established traditional procedure. This vinegar is made from only two local grape varieties—lambrusco and trebbiano—and must age for a minimum of 12 years; if it says stravecchio (extra old) on the label, it has aged for 25 years or more. Some even age for 50 years or longer. These vinegars represent the pinnacle of the category.