There are two basic types of balsamic: the highly prized, DOP-regulated, aceto balsamico tradizionale, or traditional balsamic vinegar—and then there’s everything else.

Much like the olive oil market, the world of balsamic vinegar has been so adulterated that what most consider balsamic vinegar has nothing in common with the real thing. To understand what differentiates the daunting number of balsamics that line market shelves is a complicated and difficult task that should begin at the top. Aceto balsamico tradizionale is the pinnacle of all vinegars: it’s produced by hand in small quantities, using traditional methods.

In order to bear the name aceto balsamico tradizionale, every aspect of its creation, from grape to bottle, is carefully regulated by DOP standards. This vinegar undergoes a lengthy transformation, starting as unfermented juice pressed from indigenous white Trebbiano grapes (although Lambrusco and other varietals are sometimes used), which is simmered in large, copper cauldrons for about 24 to 42 hours. This concentrated syrup, known as mosto cotto, is aged in a series of five barrels of varying sizes and types of wood known as a batteria. The wood can range from acacia, cherry, oak, chestnut, mulberry, ash and sometimes juniper. Fitted with large openings that are covered with loosely woven fabric, which allow oxygen to concentrate the must, the five barrels of a batteria range from large to small, reflecting the concentration and length of time the vinegar has been reducing.

During the minimum 12 years DOP balsamic must age, fluctuations in temperature improve the quality of the vinegar, so the barrels are kept in upper attic spaces, or in a shed-like room known as an acetaia. It is important to understand that balsamic doesn’t “age” in the same way wine does. Where a single vintage of wine ages in barrels and bottles, a balsamic’s age refers to the length of time the vinegar maker, or acetaio, has worked with a blend; not the age of the contents in a bottle.

For instance, as the vinegar becomes concentrated over time, the content of each barrel must be replenished (topped up) to prevent solidification. This task begins with the smallest and most concentrated barrel in the batteria being filled with younger vinegar from the next largest barrel, and so on, down the line to the largest barrel, which is the youngest and the least concentrated. This barrel is filled with an addition of freshly cooked must. The process is repeated yearly, until the contents of the smallest barrel reach the desired age and flavor. These barrels hold the prize; it is this vinegar that goes to market—but only if it passes rigorous taste and purity tests.

To keep competition fair, each producer is allotted a specific number of bottles of aceto balsamico tradizionale that they can sell, which is indicated by a numbered tag around the bottle’s neck. Bottles from Modena are characteristically bulb-shaped, while bottles used in Reggio nell’Emilia are bell-shaped. Colored caps designate age: a red cap denotes a vinegar aged at least twelve years, while a gold gap honors a vinegar of twenty-five years or more known respectfully as il Patriarca.