Ground mustard seed with no liquid added. The heat only appears when it meets water, which triggers an enzyme reaction that produces the pungent compounds.
What it does in a recipe: Pungency and emulsifying power - it stabilises vinaigrettes and cheese sauces as well as adding sharpness. Pick the swap that covers that job - the ratios below are written so you can act on them without doing any arithmetic.
Also called: Dry mustard, Ground mustard, English mustard powder
Prepared mustard is the powder already hydrated and acidified, so three times the volume delivers a similar amount of seed with the water already added.
MethodReduce the recipe's other liquid to compensate, and add it later than you would the powder since its pungency is already developed and fades with heat.
Trade-offBrings vinegar, salt and often turmeric colouring. In a dry rub or a dry mix it will not work at all.
Allergen checkPrepared mustards vary in composition and some, particularly wholegrain and speciality varieties, include wheat flour or are made on shared equipment. Read the jar before serving to anyone avoiding gluten, and take a diagnosed allergy to the manufacturer.
Allergen checkMustard itself is a declarable allergen in the UK and EU, and some prepared versions also contain wheat or sulphites. Check the label before serving to anyone with restrictions, and confirm a serious allergy with the producer rather than assuming.
Allergen checkMost powders sold as wasabi are horseradish and mustard with colouring, and some include wheat starch as a binder. Read the ingredient list before using one in a gluten-free dish, and verify with the maker where an allergy is medical.
Worth knowing
Mustard powder needs about ten minutes in cold liquid to reach full strength, and hot liquid destroys the enzyme before it works. Mix it with cold water first, then add it to the hot pan.
At a glance
Mustard powder in summary
Mustard powder at a glance: category, its job in a recipe, the diets it suits, the diets its substitutes can satisfy, and how many substitutes there are.
Can I use yellow mustard seed, ground instead of mustard powder?
1 tsp mustard powder = 1 tsp yellow mustard seed, finely ground. It is the identical ingredient one step earlier, and the volume works out close to even because the seeds are small and dense. Effectively identical, and fresher than a powder that has been open a year.
Can I use prepared yellow mustard instead of mustard powder?
1 tsp mustard powder = 1 tbsp prepared yellow mustard, with 2 tsp liquid removed elsewhere. Prepared mustard is the powder already hydrated and acidified, so three times the volume delivers a similar amount of seed with the water already added. Brings vinegar, salt and often turmeric colouring. In a dry rub or a dry mix it will not work at all.
Can I use dijon mustard instead of mustard powder?
1 tsp mustard powder = 1 tbsp Dijon, with 2 tsp liquid removed elsewhere. Dijon is made from brown mustard seed with white wine or verjuice, so it carries more heat and aroma than yellow mustard at the same volume. Sharper and more wine-like. It emulsifies a vinaigrette at least as well as the powder does.
Can I use wasabi or horseradish powder instead of mustard powder?
1 tsp mustard powder = 1/2 tsp horseradish or wasabi powder. All three plants are Brassicaceae and produce their heat through the same isothiocyanate chemistry, but horseradish is considerably more potent. A sharper heat that hits the sinuses rather than the tongue, and no emulsifying benefit in a dressing.
Cooking around an allergy? Diet tags here describe the ingredient itself, not any particular brand. Processed products change formulation without notice and shared production lines are common, so read the label on everything you use. A severe allergy is a medical matter - confirm with the manufacturer or your clinician rather than relying on a substitution chart.