Published June 1, 2008. From Cook's Country.
Tasters want more heat, less acid.
To be labeled Dijon, a mustard must adhere to the formula developed more than 150 years ago in Dijon, France. Finely ground brown or black mustard seeds are mixed with an acidic liquid (vinegar, wine, and/or grape must) and sparsely seasoned with salt and sometimes a hint of spice. Dijon should be smooth and have a clean, nose-tingling heat. To find out which Dijon mustard is best, we rounded up eight nationally available brands and tasted them plain and in a simple mustard vinaigrette. What did we find out?
Our tasters preferred spicier mustards. The three hottest mustards were our tasters’ overall favorites. Interestingly, when we measured the pH level of each brand, this hot trio also proved to be the least acidic. (Note that a higher pH value equals lower acidity.) A peek inside the mustard- making process explains why. When mustard seeds are ground, an enzyme called myrosinase is released. The myrosinase activates the mustard’s dormant heat-producing chemicals (called glucosinolates), but the addition of acid retards this reaction. So less acid produces a mustard with more heat-producing chemicals. These heat-producing chemicals, however, are volatile and will dissipate over time. For this reason, we recommend checking “use by” dates, buying fresher mustards when possible, and never storing Dijon for more than six months.
What other qualities mattered? The presence or absence of wine in these mustards did not impact results: Grey Poupon has it, but Maille and Roland do not. Country of origin didn’t matter either, as Grey Poupon is made in the United States, Maille in Canada, and Roland in France. What was important was balance. Mustards that were too acidic, too salty, or muddied with other flavors were downgraded by our tasters.