Karashi substitute

Best substitute

English mustard (Colman's or similar)

Use the same amount as the karashi you are replacing

Best for oden

Close match

English mustard, and Colman's in particular, is the closest thing on any supermarket shelf and swaps in at 1:1 - the heat level and the way it rushes up your nose are almost identical. Even better, if you have English or brown mustard powder in the cupboard, mix 1 teaspoon of it with 1 teaspoon of cold water and let it stand 10 minutes: that is essentially karashi, made the same way from the same seed. Chinese hot mustard is also effectively interchangeable. Do not reach for American yellow mustard, which is sweet and vinegary and will taste plainly wrong on oden or natto.

Other karashi substitutes

Ranked, with the exact amount to use

2Mustard powder mixed with cold water
Close match
1 tsp brown or English mustard powder to 1 tsp cold water, stand 10 minutes
In practical terms this is not a substitute at all, it is karashi.
What changes
Japanese karashi powder is ground brown mustard seed, the same seed used in English mustard powder, and the method is identical: cold water, stir to a paste, wait ten minutes for the pungency to develop. Made this way it is paler and cleaner-tasting than any prepared tube, with no vinegar sourness and no turmeric colour, and it is the freshest and fiercest version you can have.
Best for
oden and hot pot, natto, shumai, karashi-sumiso and other dressings, any recipe that specifies karashi
The water must be cold. The heat is created by an enzyme reaction when the dried seed meets water, and hot water destroys the enzyme, leaving a bland yellow paste - this is the single most common mistake. Avoid mild yellow mustard powders, which are made from the gentler white seed. Mix only what you need, since it starts fading within the hour.
3Chinese hot mustard
Close match
Use the same amount
Practically interchangeable, and for the same reason - it is another powder-and-water mustard made from brown seed, with the same explosive nose heat that arrives fast and disappears fast.
What changes
If you have a sachet from a takeaway or a jar from an Asian grocer, use it exactly as you would karashi. The only difference worth noting is that Chinese hot mustard is often a touch more bitter and slightly sharper, since it is usually mixed fresh and served immediately at full strength.
Best for
shumai and gyoza, oden, tonkatsu, dipping fried food, dressings
Sachets that have been in a drawer for a year are much weaker than fresh, since mustard pungency fades. If you are mixing it from a powder sachet, use cold water and give it the full ten minutes. Start with less than you think, as freshly mixed Chinese mustard can be startlingly hot.
4Wasabi paste
Different taste
Use about half as much as the karashi called for
The sensation is right - wasabi and mustard both produce that sharp volatile heat that goes up the nose and clears in seconds, and most tube wasabi is actually horseradish and mustard anyway, so chemically you are in the same territory.
What changes
The flavour and the colour are what give it away: wasabi brings a distinct grassy, faintly sweet green note and will tint the plate. On tonkatsu or shumai it reads as the wrong region even when it works. Whisked into a mayonnaise or a dressing, nobody notices at all.
Best for
karashi-mayo and dipping sauces, dressings, shumai, at a pinch, seafood
Halve the quantity to start with, because tube wasabi is usually mixed to a stronger concentration than prepared karashi. Do not use it in oden, where a dab of pale mustard on the side is part of how the dish looks and where the green is jarring. Old tubes lose their punch quickly, so a long-opened one may need the full amount.
5Prepared horseradish, drained
Taste and texture differ
About 1 ½ times the amount of karashi called for, squeezed dry
Right sensation, wrong flavour, and wet.
What changes
Horseradish gives the same nasal sharpness, which is the essential thing karashi contributes, but it is packed in vinegar so it tastes distinctly sour and earthy-rooty rather than clean and bitter-hot. It is also full of liquid, which will loosen a dipping sauce or run across a plate of oden. Squeeze it in a paper towel first and it becomes a usable stand-in rather than a mess.
Best for
dipping sauces and mayonnaise, when there is no mustard of any kind in the house, beef and pork
Use plain prepared horseradish, not creamy horseradish sauce, which is diluted with dairy and sugar and is far too mild and sweet for this job. Jarred horseradish fades in the fridge over months, so taste it before you decide how much to use. It adds a sour note that karashi does not have, so use it where a little acidity will not hurt.
6Dijon mustard
Different taste
Use the same amount for colour and volume, but expect much less heat
Worth including for what it is - a stopgap that looks right and tastes clearly weaker.
What changes
Dijon is made from brown seed, so the raw material is correct, but it is mixed with white wine or verjuice rather than water, which mellows the pungency dramatically. The result is noticeably sour, winey and only mildly warm, and its heat sits on the tongue rather than clearing the sinuses. It will not deliver the point of karashi, which is a short sharp jolt that cuts through fat.
Best for
dressings and mayonnaise, where sourness is welcome, when it is the only mustard available, tonkatsu, where the sauce carries the dish anyway
If Dijon is all you have, stir a pinch of dry mustard powder into it to bring some of the nose heat back, or add a small dab of wasabi. Whole-grain Dijon is milder still and the seeds are wrong texturally for a smooth dab beside oden. Use rather more than the recipe says and accept a gentler dish.
7American yellow mustard (not recommended)
Different taste
Half the amount of karashi, if you must
Included so you know to avoid it.
What changes
American yellow mustard is made from mild white mustard seed with a great deal of vinegar, sugar and turmeric, which makes it sweet, sharply sour and barely hot - the opposite profile to karashi in almost every respect. On a hot dog it is excellent. On oden, natto or a steamed shumai it tastes like a mistake, contributing sweetness and vinegar where the dish needed a clean hit of heat to cut richness. If it is genuinely all you have, use half as much and expect the dish to taste sweet-sour rather than sharp.
Best for
nothing in this category, honestly, absolute last resort in a mayonnaise-based dressing
A better last resort than yellow mustard is nothing at all plus a squeeze of citrus or a splash of ponzu, which at least gives the dish acidity rather than sugar. If you have any mustard powder in the cupboard, even in an old spice tin, mix it with cold water instead - it will be far closer.

What is Karashi?

Karashi is Japanese mustard - a fierce pale-yellow paste made from nothing but ground brown mustard seed and water, sold either as a powder or ready-mixed in small tubes labelled neri karashi. It carries none of the vinegar, sugar or turmeric of Western mustards, so all it adds to oden, natto or a pork cutlet is a clean jolt of heat that cuts fat and funk.

Cooking tips

Karashi's whole job is a short jolt of volatile heat that cuts through fat and funk, and it does that job with nothing else attached. Because it contains no vinegar and no sugar, it adds no sourness and no sweetness to the plate, which is why substituting a Western mustard changes the balance of the dish and not just its heat. When a swap tastes wrong, the culprit is almost always the vinegar or sugar the substitute brought with it.
Mix karashi powder with cold water and let it stand 10 minutes before serving. The pungency does not exist in the dry powder - it is generated by an enzyme when the powder meets water, and hot water denatures that enzyme, leaving a bland yellow paste with no bite at all. This is the same rule that governs English mustard and wasabi powder.
The heat is short-lived by design, so mix small amounts as you need them. Karashi is at its fiercest around ten to twenty minutes after mixing and has noticeably faded within an hour, and a tube that has been open for months is much milder than a fresh one. There is no way to store fresh-mixed karashi at full strength.
Use far less than you would of Western mustard. A pea-sized dab per portion is normal for oden or shumai, and it is meant to be picked up in tiny amounts on the tip of a chopstick rather than spread across the food. A teaspoon of karashi is a great deal of karashi, and Western-sized portions will overwhelm a delicate broth.
Never simmer it into a sauce or add it early to something hot. Stir it in off the heat at the very end, exactly as you would with wasabi. A couple of minutes at a boil destroys the pungency completely and leaves only bitterness, which is why mustard added to a hot dressing so often tastes harsh and flat.
Karashi turns up in more than dipping form, and a powder-and-water version works perfectly in all of them: karashi-mayo for fried chicken and sandwiches, karashi-sumiso which is a mustard and white miso dressing for vegetables and seafood, and karashi-renkon, the Kumamoto dish of lotus root stuffed with mustard-miso paste.

Frequently asked questions

What is the best substitute for karashi?

English mustard, either from a tube or made up from Colman's-style powder, at a straight 1:1. It is made from the same pungent brown mustard seed and delivers the same fierce nose heat, and the only differences are a little vinegar and turmeric in the prepared version. If you have the powder rather than the paste, mixing 1 teaspoon of powder with 1 teaspoon of cold water and waiting 10 minutes gives you something essentially identical to real karashi.

Can I use regular yellow mustard instead of karashi?

You can, but you should know what happens. American yellow mustard is made from mild white mustard seed with a lot of vinegar, sugar and turmeric, so it is sweet, sour and barely hot - close to the opposite of karashi's clean, fierce, unsweetened heat. On oden, natto or shumai it tastes noticeably wrong rather than merely different. Use half the amount if you have no choice, and check the back of your spice cupboard for mustard powder first, which will be far closer.

Can I just leave the karashi out?

It depends on the dish. With tonkatsu, korokke or gyoza, the sauce or dipping soy is carrying the dish and a missing dab of mustard is a minor loss, so leaving it out is fine. With oden and natto it is doing real work - cutting the fat of the simmered ingredients in one case and the funk of the fermented soybeans in the other - and the dish genuinely tastes flat without it. In those cases use English mustard or a small dab of wasabi rather than skipping it.

Is karashi the same as Chinese hot mustard?

Essentially yes, for cooking purposes. Both are made by mixing ground brown mustard seed with water and nothing else, and both produce that fast, fierce heat that clears the sinuses and vanishes in seconds. They swap 1:1 in either direction. Chinese hot mustard is often a shade more bitter, largely because it tends to be mixed fresh and served at full strength, but the difference is small enough that a takeaway sachet will serve perfectly well in place of a karashi tube.

Why is my karashi not spicy?

Three likely causes. You used warm or hot water, which destroys the enzyme that creates the pungency - it must be cold. You did not wait long enough after mixing, since it needs a full 10 minutes to develop. Or the powder or tube is old, because mustard pungency degrades steadily and a tube opened months ago can be a fraction of its original strength. Test a fresh half teaspoon mixed with cold water; if that does not sting, the product is finished.

Is karashi gluten-free and vegan?

Karashi powder mixed with water is nothing but mustard seed and water, so it is both. Prepared tubes are a different matter and need checking, because many neri karashi products add vinegar, oil, starch and sometimes wheat as a thickener. The same caution applies to substitutes: prepared English mustard commonly contains wheat flour, and some mustards use wine. If either restriction matters, buying plain mustard powder and mixing it yourself is the simplest safe route.

Related substitutes

More sauces & condiments substitutes

Karashi substitute

Other karashi substitutes

2Mustard powder mixed with cold water

3Chinese hot mustard

4Wasabi paste

5Prepared horseradish, drained

6Dijon mustard

7American yellow mustard (not recommended)