What Makes Mustard Spicy?

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By Dr. Mercola

Everyone has individual likes and dislikes, especially when it comes to heat in their food. Look at the menus at certain restaurants, for instance, and you might find tiny jalapeno icons next to certain dishes to signify their heat level. One jalapeno means mildly hot; five indicate as fiery as they can make it.

A perfect example of a food — or rather a condiment — that’s very popular and comes in widely varying degrees on the heat index is mustard, which can definitely rival jalapenos in the heat index. Some like it hot, as the saying goes.

There are multiple varieties of mustard to satisfy your cravings, but have you ever wondered what provides the flavor and heat? There’s actually a plant known as mustard, a Brassica (or more scientifically, a Brassicaceae, sometimes referred to as mustards) correctly and its seed is the agent, in a matter of speaking, that supplies the spice.

In and of themselves, tiny, round mustard seeds aren’t hot or spicy. It’s when they’re ground or broken open and mixed with liquid that the zing emerges. There are a few types of mustard seeds: white, brown and black. White mustard seeds produce heat on your tongue, but it’s the darker seeds that impart the pungent essence in your nose. This type of flavor is longer-lasting and more intense.

That’s why the traditional yellow mustard you’re probably familiar with requires white mustard seeds, and the stronger varieties of this popular condiment come from using darker seeds. In fact, yellow mustard is the second most-used condiment in the U.S., no doubt because it works so well with so many types of meat as well as seafood. Experimenting with different types of mustards is a tasty way to get acquainted with all the different types.

Mustard: The Science Behind the Heat

One of the compounds in mustard seeds that imparts the aforementioned zing is called sinigren, a glucosinolate or natural constituent of pungent plants found in this Brassica veggie.

When sinigren is broken down, it emits an enzyme called myrosinase, and that in turn creates mustard oil. It’s the oil that produces the heat when liquid is added, such as cold water. It’s so strong that if you should attempt to make your own homemade mustard, the heat can burn and blister your skin. Savvy mustard makers wear protective gloves for this reason.

The process doesn’t happen immediately. It takes about 15 minutes for the chemical process of turning up the heat to take place and reach its peak intensity. Because this intensity begins to rapidly diminish, the process of making the spicy condiment requires the addition of an acidic agent to stop the flavor degeneration. Unfortunately, the acidic agent brings about a flavor that masks that of the mustard itself. So does heat.

Warm temperatures can also obstruct the strength of the mustard (known as “prepared spicy mustard”), so if you want to make your own (directions are at the bottom), make sure the liquid you add to the mix is at least room temperature. It must be noted that myrosinase is crucial in the conversion of glucosinolates into isothiocyanates, because that’s where its chemoprotective elements come from.

As a matter of fact, you can “stack” the benefits by eating more than one type of Brassica vegetables together. Organic mustard seed powder is a powerful way to do it.

Mustard History: The Back Story

Like most other plant-based foods, mustard is ancient. The early Romans and, later, the French ground the seeds and mixed them with wine to create a paste fairly similar to the way we eat it today. In fact, the English name means “burning must,” must being the unfermented juice of wine grapes.

Greek scientist Pythagoras in the sixth century B.C. reportedly used mustard on scorpion stings, and Hippocrates used it for poultices and other medicine, such as mustard plasters for toothaches. Even before the spice trade became a “thing,” The Spruce notes:

“The Romans took the mustard seed to Gaul, where it was planted in vineyards along with the grapes. It soon became a popular condiment. French monasteries cultivated and sold mustard as early as the ninth century, and the condiment was for sale in Paris by the 13th century. In the 1770s, mustard took a modern turn when Maurice Grey and Antoine Poupon introduced the world to Grey Poupon Dijon mustard. Their original store still can be seen in downtown Dijon.”1

While the mustard plant has been traced to Europe, it actually has more worldwide origins. You’ll find more than 40 varieties, which is why there’s “Chinese mustard,” “Indian mustard” and “German mustard.” Most are based in one of three continents: Africa, North America and Asia.

Today, the highest production in the world does have more to do with the seeds than the leaves, but altogether the highest producers in 2015, in order, were Canada, Nepal, Myanmar, Russia, Ukraine, China, the U.S., France, the Czech Republic and Germany.

Nutritional and Medicinal Aspects of Mustard

Mustard seeds aren’t the only useful part of the plant. The leaves also have nutritional, culinary and even medicinal applications. They’re used in salads, usually mixed with other greens, and can be combined with select other items, such as walnuts and wine vinegar or avocado oil, and sautéed.

According to the George Mateljan Foundation, a not-for-profit foundation dedicated to helping people eat and cook for optimal health, mustard greens are a cool season crop, so in the U.S. they can be planted similarly to lettuce. Most production is in the Northwest and upper Midwest, such as North Dakota, Idaho, Washington, Montana and Oregon. Additionally:

“Because purple and red mustard leaves are becoming more popular in many grocery stores, don’t be surprised to find mustard ‘greens’ that are actually vibrant purple or purple/red in color. Red Giant, Ruby Streaks, Purple Osaka, Garnet Giant, Japanese Red, and Scarlet Frills are varieties that you might find in your local supermarket.”2

Phenols are some of the most hard-working antioxidants. The term encompasses such phytonutrients as flavonoids, and mustard greens contain some of the highest levels among veggies, along with other leafy greens: collard greens, kale and purslane, which contain kaempferol, isorhamnetin, quercetin and ferulic acid.

In addition, other than kale, mustard greens contain the highest concentration of isorhamnetin, a phenolic scientists have been studying for years in relation to its dramatic and beneficial impact on cancer, as well as isothiocyanates (ITCs), which are sulfur-containing nutrients.

The George Mateljan Foundation adds that mustard greens are included in a list of vegetables containing high levels of ITCs, and “mustard greens easily came out on top!”3 The leafy veggie is among the top vegetables worldwide in terms of its excellent vitamins K, A and E, calcium and iron content. Copper, vitamin B2, manganese, protein, vitamin C, vitamin B6 and phosphorus levels in mustard greens are also very high.

Sinigren: One of Mustard’s Hardest Working Nutrients

As for the sinigren content, one study conducted at North-West University in South Africa mentions it in regard to its notation in Ayurvedic texts for its natural pharmaceutical properties:

“Studies conducted on the pharmacological activities of sinigrin have revealed anti-cancer, antibacterial, antifungal, antioxidant, anti-inflammatory, wound healing properties and biofumigation.”4

The benefits of sinigren are multidirectional, positively impacting your liver and pancreas.5 There are also a number of powerful health benefits from the sinigren (Allyl isothiocyanate or AITC) content in mustard and other Brassica vegetables, including the suppression of:6

  • Bladder and liver cancers — An animal study showed that pure sinigren inhibited bladder cancer growth by nearly 34 percent and blocked its muscle invasion by 100 percent.7 Liver cancer cell proliferation also showed “significant downregulation” and metastasis suppression due to AITC.8
  • Postprandial hypertriglyceridemia — Risk factors for cardiovascular disease include high blood triglyceride concentrations, which were lowered in another study.9
  • Antimicrobial effects — E. coli and other foodborne pathogens may be inhibited, along with several damaging cellular structures and metabolic pathways, due to the presence of glucosinolate sinigrin.10
  • Studies showed a link between AITC intake and the incidence of stomach and lung cancers.11
  • Antioxidants in AITC showed that another Brassica vegetable, Brussels sprouts, when cooked, was DNA protective.12

Another Spicy Plant-Based Food: Horseradish

Apart from the heat derived from jalapenos or ghost peppers, there’s an array of interesting plant-based foods to please your palate. Horseradish is another example. Armoracia rusticana (horseradish) is a perennial Brassicaceae in the same family as the rather tame broccoli and cabbage, but a few in the family are quite warm, such as radishes and wasabi.

Studies show horseradish, too, has a number of cancer-protective compounds, some the same, such as sinigren, and others slightly different, such as phosphatidylcholines, alpha-tocopherol and ubiquinone, than those in mustard. One study indicates that the growth of colon, lung and stomach cancer cells was inhibited by various but impressive degrees.13

Nutritional aspects of horseradish are varied and plentiful. It contains vitamin C, fiber, potassium, magnesium, zinc and manganese. Organic Facts14 lists a number of health advantages that studies show can result from consuming horseradish, as it:

Boosts your disease immunity

Strengthens your bones

Contributes to weight loss

Contains diuretic properties

Acts as an antibacterial

Helps in pregnancy

Improves digestion

Boosts your metabolism

Reduces blood pressure

Improves respiratory conditions

Interestingly, the unique, pungent qualities of horseradish’s allyl isothiocyante compounds could be described as plant-based “defensive poisons,” according to Nature’s Poisons:

“If you’ve ever been around a horseradish plant, or fondled a root, you’ve noticed that there is no animosity towards you. No odor, no burning of the eyes, no nothing.

That’s because the magic of horseradish is contained within the horseradish cells … When the leaves or roots of a horseradish plant are chewed by a predator, the cells are burst open and release sinigrin, a glucosinolate. When exposed to sinigrin … nothing happens. But wait, also released from the cells is the enzyme myrosinase.”15

The article goes on to explain that myrosinase acts as a catalyst or “grenade” that hydrolyses or adds water to sinigrin to turn it into glucose and allyl isothiocyanate, which can (and usually do) act as a serious eye irritant and burn your lungs when you breathe it in, not to mention the smell. Animals hate it and usually steer clear of it.

How to Make Mustard and Horseradish Sauces

Also according to Nature’s Poisons, the conversion of sinigren into allyl isothiocyante changes the pH from a neutral pH of 7 to a more acidic pH of 4. In the process, a compound known as aglycone converts to allyl cyanide, but don’t worry; your body metabolizes and disperses it throughout your body. You can grow horseradish easily if all you have is a root and some dirt. However, note that it is an invasive plant, growing quickly in areas you might not want it. Making your own prepared horseradish is as simple as this:

“Finely grate horseradish root in a ventilated space, wait a few minutes for the chemistry magic to happen, and once the desired “hotness” of the horseradish is reached, add acidic vinegar. Done. Simple as that. Pretty cool, huh?”16

According to The Spruce,17 the procedure for making your own version of mild yellow mustard is quite simple as well. This recipe makes enough to fill two 4-ounce jars, which you can sterilize during the cooking process. The mustard can be stored in the refrigerator for as long as a year. Cut the recipe in half to make less.

Ingredients for Homemade Yellow Mustard

  • 1/2 cup dry-ground yellow mustard seed powder
  • 1/2 cup water
  • 1/3 cup apple cider (or distilled white) vinegar
  • 1 teaspoon all-purpose flour
  • 3/4 teaspoon natural salt
  • 1/4 teaspoon turmeric
  • 1/8 teaspoon garlic powder


  1. Add cold water to the mustard seeds, then whisk all the ingredients together in a small saucepan until smooth and it becomes a liquid. Boil over medium heat for seven to eight minutes, stirring occasionally.
  2. Remove the saucepan from the heat to cool for five minutes, during which time it will begin to thicken (a process that can continue for as long as two days).
  3. Transfer the mustard to the jars and fasten the lids securely. Let cool to room temperature before refrigerating.

An important note is that sampling your mustard in less than 24 hours after making it is not recommended; you must cool your heels at least 24 hours as the result will otherwise be “disgustingly bitter.” The flavor will mellow, and it will be worth the wait.

Source:: Mercola Health Articles