What Makes Mustard Spicy?

Ever wondered why some mustards pack a fiery punch while others offer a milder, more subtle kick? The secret lies in understanding the different types of mustard seeds and the interplay between seeds and liquids. Controlling the heat of mustard is both an art and a science, requiring a balance of ingredients and techniques. Do you prefer a gentle warmth or a fiery explosion of flavor?

My favorite mustard is this sweet, hot mustard that we love to eat in Scandinavia. It stores well for a long time, makes a nice present, and goes well with many dishes, such as sausages, cured salmon, hamburgers, and sauces.

Different types of mustard seeds

Mustard seeds come in three main varieties, each with distinct characteristics that influence the flavor and heat of the mustard you create:

1. Yellow Mustard Seeds (Sinapis alba): Yellow mustard is mild and slightly sweet, with subtle earthiness. They are sometimes also called white mustard seeds. Yellow seeds are the foundation of classic American yellow mustard. They are also used as a pickling spice. With yellow mustard powder you can make both quite strong and hot mustard or mustard that is very mild and not at all hot. Below you can read more on how to affect heat.
2. Brown Mustard Seeds (Brassica juncea): Brown seeds are spicy and robust with a slightly bitter undertone. A staple in making dijon mustard. Brown seeds are usually incorporated when making whole-grain mustard varieties. Indian cuisine also uses black/brown mustard seeds for example in may curries.
3. Black mustard seeds (Brassica nigra): There are over numerous varieties of mustard seeds. Black ones are intensely hot and pungent with a peppery kick. Black ones can be used as substitute for brown ones, since they are very alike, but you might want to adjust the amount.

Understand the science

If you’ve ever wondered why some mustards are fiery enough to make your eyes water while others are mild and earthy, the answer lies in the science behind its heat and flavor.

The characteristic heat and pungency of mustard come from compounds called isothiocyanates. These are created when mustard seeds are crushed and mixed with water, releasing enzymes that break down parent compounds like sinigrin and sinalbin. These parent compounds are types of glucosinolates—naturally occurring chemical compounds found in mustard plants and other members of the Brassica family, such as broccoli and horseradish.

Here’s how the process works:

1. Crushing the Seeds: When mustard seeds are ground or crushed, the enzyme myrosinase is activated.
2. Mixing with Water: This enzyme reacts with glucosinolates (sinigrin in black mustard seeds, sinalbin in yellow mustard seeds), converting them into isothiocyanates.
3. Isothiocyanates = Heat: These isothiocyanates are, what give mustard its signature sharpness and heat.

The type of glucosinolate present determines the flavor profile of the mustard. For example, sinigrin, found in brown and black mustard seeds, produces a sharp, spicy flavor, while sinalbin, found in yellow mustard seeds, leads to a milder, more earthy taste.

How to affect the heat?

The heat of mustard can be manipulated by altering how the isothiocyanates are produced and preserved:

• Temperature Matters: Heat during preparation can deactivate the myrosinase enzyme, resulting in a milder mustard. Cold water preserves the enzyme’s activity, producing a more pungent product.
• Timing is Key: Freshly prepared mustard is at its most pungent, but over time, the isothiocyanates break down, mellowing the flavor.
• Vinegar as a Stabilizer: Adding vinegar or another acid halts the enzymatic reaction and locks in the mustard’s flavor at its current level of spiciness.

Mellow it down

If your mustard is too sharp or spicy for your liking, there are several ways to mellow its flavor. Allowing the mustard to age in the refrigerator for several days to a week will naturally reduce its pungency as the isothiocyanates break down over time. Adding a sweetener, such as honey or sugar, can balance the heat with a touch of sweetness. Additionally, blending in creamy elements like mayonnaise can help tone down the sharpness while creating a smoother, more balanced condiment.

If you like creamy soft and sweet mustard with some subtle heat you need to test the traditional Finnish Christmas mustard with some heavy cream.

Traditional coarse dijon mustard is made with brown and yellow mustard seeds, white wine, vhite wine vinegar, salt and if you want to, some sweetness from sugar or honey.

Explore flavor fusions

I love the flavor that a brief toasting adds to a dish. Just use a dry skillet over medium- high heat until the mustard seeds start to pop and become fragrant.

Mustard’s versatility makes it the perfect canvas for experimenting with bold combinations. Consider blending your mustard with:

• Fruits: Puréed berries, apricots, or citrus zest for a fruity twist. Apricot chicken with mustard is a well known dish.
• Herbs: Fresh rosemary and thyme infuses your mustard with earthy undertones.
• Spices: Incorporate curry powder, smoked chili flakes, or even cinnamon. The famous Swedish Christmas mustard has asses cinnamon, coriander and nutmeg as spices.
• Sweeteners: Maple syrup, agave, sugar syrup, and even molasses adds a subtle sweetness that complements the mustard’s tang.
• Alcohols: Mix in a splash of bourbon, sherry, or even stout beer for a robust, sophisticated flavor profile. My mum´s favorite was cognac mustard.

Craft unique mustards that pair perfectly with dishes, from grilled meats to cheese boards. The possibilities are limited only by your imagination!