Dijon Mustard

When Grey Poupon first posed its famous question to American television audiences 34 years ago, the company’s sophisticated French-style mustard (which is actually made in the United States) wouldn’t necessarily have been a pantry staple in most households. But over the years our taste for (and sales of) this spicy, smooth condiment has grown—to the tune of more than $45 million worth of mustard sold by Grey Poupon in this country each year.

In the test kitchen, we understand the appeal. Good Dijon mustard is creamy, with more body than conventional yellow mustard, and packs a wallop of clean, nose-tingling heat. We slather it on sandwiches, squirt it on hot dogs and sausages, and add it to everything from salad dressings and dips to pan sauces and glazes for roasted meats, fish, and vegetables.

When we last tasted Dijon mustards in 2008, Grey Poupon was our favorite for its “bold” yet “balanced” heat, but lately we’ve wondered if any other producers could top it. To find out, we purchased 10 Dijons made in the smooth style developed in France in the 1300s (we ignored coarse- and whole-grain products), tasting them plain and, to see how they paired with savory food, on boiled hot dogs.

As expected, clean flavor, intense heat, and creamy body were exactly the qualities we liked in a Dijon. Those that were “sweet,” “too mild,” or seasoned with ingredients beyond the standard formula simply didn’t meet our expectations for what Dijon should be.

Some Like It Hot

The sources of those unexpected flavors became obvious when we scanned the package ingredient lists. All the bottom-ranking mustards contained “spices” or other seasonings. The worst offender—loaded with garlic, celery seed, paprika, sweeteners (including high fructose corn syrup), and thickeners—actually “ruined a hot dog” for some tasters. Our favorite mustards stuck closer to the minimalist traditional French recipe: just mustard seeds, water, vinegar, salt (we preferred those with at least 100 milligrams per serving), and a few preservatives.

And what gave a mustard a good dose—or not—of heat? The answer wasn’t quite as obvious as how high on the ingredient list mustard seeds appeared. It turns out that the acidity of the condiment, which comes from vinegar and sometimes from wine as well, can also affect its spiciness. That’s because too much acidity can kill heat-producing compounds in the mustard seed called isothiocyanates. Sure enough, when we had an independent lab measure the pH of each sample, the values tracked with our heat assessments: Tasters found the Dijons with lower pHs (and thus greater acidity) to be the least spicy—even “a bit bland” on a hot dog—whereas mustards with relatively high pHs earned praise for “full, intense mustard flavor.”

Another surprising indicator of a mustard’s heat: fat content. While the majority of these Dijons contained no fat, our favorites had a tiny amount—just 0.5 grams per serving. It turns out that mustard seeds are the only ingredient in most Dijons that contains fat. Therefore the Dijons listing fat were likely to contain more mustard seeds than other products, which helped to explain their more potent heat.

Finally, we knew from a previous Dijon tasting that mustard’s pungent isothiocyanate compounds are highly volatile and will fade with time or exposure to air. In fact, oxidation can even occur slowly inside new, unopened containers of mustard. All the Dijons we tasted contain preservatives that can help inhibit oxidation, but it turns out that the type of preservative used can influence heat. While our top three mustards included some form of sulfite or sulfur dioxide, most of the others relied on tartaric acid. Sulfur dioxide renders oxygen inactive, which makes it a very effective stabilizer, but tartaric acid merely removes traces of iron that promote oxidation, so it’s less effective.

All these other factors being equal, the best way to ensure that your mustard will pack some heat is to buy the freshest possible product. The problem is that manufacturers don’t make determining the age of a product easy. For one thing, a mustard’s shelf life can range from six months to two years, depending on the manufacturer, and is not printed on the label—making it hard to know whether a mustard that’s, say, five months away from a sell by date is still very fresh or getting close to the end of its time. (We determined the age of the mustards in our tasting by calling the manufacturers to find out their shelf life.) What’s more, some brands print a cryptic manufacturing code that corresponds to a production date rather than an actual sell-by date. Even with this ambiguity, our advice is to, when possible, buy a mustard that does list a sell-by date, and make sure that date is as far away as possible.

Cuts the Mustard

Our favorite mustard brought together all the traits we were looking for. Its pH was the highest of all the mustards in the lineup (3.80 versus 3.49 in the loser), and it contained a small amount of fat; in fact, it was the only mustard we tasted to list mustard seeds as the first ingredient. (Incidentally, it’s also the only widely available supermarket Dijon produced in France.) It wowed tasters with the “sharp, nasal-clearing,” “long, slow burn” that we associate with good Dijon.