Though techniques and recipes can vary, laws strictly regulate the manufacture of Dijon mustard, and—like the wines of Burgundy—the product is protected by an appellation controlee, granted in 1937. The law states that only black and/or brown mustard seeds may be used in dijon mustard (the product of milder white seeds may be labeled "condiment" but never "moutarde"), and that the seeds must be mixed with either wine, wine vinegar, or verjus, which is the juice of unripe grapes. Wine vinegar, which produces a mustard which is slightly more pungent than the other liquids, is most widely used in Dijon. Salt and herbs are added—generally summer savory, tarragon, and lavender, or a combination thereof—and, with a touch of golden turmeric to heighten color (and sometimes sulfur dioxide to preserve it), the mustard is complete. Flavored mustards, with such added ingredients as green peppercorns, honey, horseradish, shallots, or, in earlier times, anchovies or truffles, have never been allowed to bear the Dijon label.