Mostarda di Cremona

The name «mostarda» comes from «mosto», grape must, and ultimately from the Latin «mustum ardens» — «burning must» — pointing to early versions in which fruit was cooked down in must and made hot with mustard. Mostarda di Cremona, the most famous of the regional Italian mostarde, became a celebrated product of the city by the 19th century and remains tied to it commercially today. Its sharpness is the work of mustard essence: it is one of the traditional partners of bollito misto, the northern Italian dish of mixed boiled meats served at Christmas and other feasts. Unlike the milder fruit-purée «mostarda mantovana», the Cremona style is defined by whole fruit and an assertive mustard bite.

The first impression is sweet and floral, like fine candied fruit, the flesh yielding but still holding its shape with a glassy bite. A beat later the mustard arrives — not on the tongue but high in the nose, a sharp wasabi-like sting that clears the sinuses and then fades. The syrup is thick and clinging. Set against a slice of rich boiled brisket or tongue, the sweetness and heat cut the fat; eaten alone, a single piece can be startlingly fierce.

Two preserving forces are at work. First, the fruit is candied — steeped and gently cooked in sugar syrup over days so that sugar slowly replaces the water in the cells, which firms the flesh and makes it translucent while protecting it from spoilage. Second comes the mustard: a few drops of mustard essential oil — chemically allyl isothiocyanate, the same volatile compound that gives mustard, horseradish and wasabi their pungency — are stirred into the cooled syrup. Because allyl isothiocyanate is volatile and heat-sensitive, it is added cold and the jars are sealed; cooking it off would blow away the very heat that defines the condiment.