Cutting the Mustard
by Gary Allen
Mustard is second only to ketchup in the pantheon of popular condiments.
All mustards start with seeds (of various colors and Brassica species). The suspended particles of ground powdered mustard or seeds, left whole, or used in combination, produce a variety of textures and flavors.
The seeds must be macerated in a liquid (typically beer, vinegar, water, or wine), but not just to extract their flavor. The maceration actually produces the hot flavor. The name “mustard” reflects this process, since it derives from the Latin mustum — the unfermented grape juice used to develop the ground seeds’ heat. Mustard gets its heat from a very different set of compounds than are found in hot peppers (or even true pepper). Rather than from capsaicin (in chiles), or piperine (in black pepper) mustard’s burn comes from acrinyl isothiocyanate (in white mustard, Brassica hirta), and/or allyl isothiocyanate (in black mustard, Brassica nigra and brown mustard, Brassica juncea). None of these compounds exists in the seeds themselves; they are created when the seeds are broken, in the presence of some form of moisture. That releases the enzyme myrosinase and several other compounds (glucosinolates; the types and relative amounts in different species accounts for their differing flavors and intensities) in the seeds that, when combined, produce their burning sensation. In addition to the compounds that deliver its heat, mustard also contains some lecithin and a form of mucilage — a gelatinous polysaccharide — that aid in thickening any sauce to which it is added.
The temperature of the liquid, as well as its acidity, determines how much isothiocyanate can be produced in those reactions. If the temperature is too high, or the pH is too low, the mustard won’t be hot. Excess heat can destroy the myrosinase before it has a chance to react with glucosinates. Hence, it is crucial that the seeds not be heated too much by the friction of milling them.
Before the eighteenth century, all mustard sauces were composed of whole or lightly crushed seeds. In 1720, a Mrs. Clements found a way to grind the seeds, removing their husks, without creating undue heat. Within a century, Jeremiah Colman was able to market a type of finely ground powder that is the basis for all modern mustards. The hottest purely mustard-based sauce is found in Chinese restaurants. It’s nothing but dry mustard (like Colman’s) reconstituted with water. Much hotter are Bajan scotch bonnet sauces, from Barbados, that use mustard as a thickener for their incendiary condiments.
Any cooked dishes that feature the heat of mustard (such as barbecue sauce — especially those from South Carolina — or simple pan sauces) must be made from mustard seeds that have already developed their isothiocyanate. This is generally accomplished by simply adding prepared mustard (though it could be done by adding mustard powder to liquid and letting it rest before cooking).
Hundreds of prepared mustards exist, around the world; entire books have been written about them, so we’ll only touch on their varieties.
American mustard comes in two basic forms: yellow mustard (usually just called “mustard”) and spicy brown mustard. Yellow mustard—such as French’s—is relatively mild and vinegary; in our house we call it “baby mustard.” It contains less mustard powder (from white mustard seeds), so it is generally thickened with a starch. Spicy brown mustard, such as Gulden’s, is coarser, with bits of brown mustard seeds visible. Some spicy brown mustards add the zip of horseradish. Many varieties of honey mustard can be found on American grocery shelves, but unlike the basic mustards, which are fairly straightforward preparations, they tend to contain many additives, such as high-fructose corn syrup, sugar, modified cornstarch, xanthan gum, invert sugar, and sodium benzoate.
French, as opposed to French’s, mustards are not bright yellow (they don’t contain turmeric). Originally made with verjuice, the tart juice of unripe grapes, most are made with white wine. Dijon mustard (named for the Burgundian town that is the center of Gallic mustard production) is finely ground brown mustard seeds, moistened with wine. “Grey Poupon,” the brand best known in the U.S., is not named for its less-intense coloration but for the two men who founded the company in the eighteenth century. Other French producers include Maille (making dozens of types, from simple Dijon mustard, to whole grain mustards, to special ones incorporating expensive ingredients, like chanterelles, cognac, morels, or black truffles). Pommery (another eighteenth-century company) makes the grainy Moutarde de Meaux. Unlike most French mustards, it does not come from Dijon but from Meaux in the Île-de-France region, near Paris, where a type of Brie is made. It’s label boasts, “If it isn’t Meaux, it isn’t Mustard,” though producers from Dijon or Düsseldorf might disagree.
ABB (Adam Bernhard Bergrath) began making mustard in Düsseldorf about fifty years earlier than Maurice Grey and Auguste Poupon set up shop in Dijon. This coarse-ground mustard is made from a mixture of seed types, and macerated in vinegar instead of wine. If it seems familiar to American diners it’s because their spicy brown mustard is based on the old Düsseldorf recipe.
In many south Indian recipes, the whole seeds are toasted or fried, thereby destroying the myrosinase. They still provide a pleasant nutty flavor, but no heat. Kasundi, on the other hand, is quite hot. It’s a form of relish originally made of fermented mustard seeds. Many versions today add canned tomato products, sugar, and vinegar. Chicago chef Tim Graham once described it as, “ketchup with a lot more going on.”
Gary Allen’s most recent food book (in print) is Sauces Reconsidered: Aprés Escoffier. His most recent non-food book (in Kindle form) is How to Write a Great Book. You can find more of his speculations about things he has been known to (but really shouldn’t) put in his mouth — his own foot being a prime example of the latter — on his website: onthetable.us.