Every good recipe deserves an equally good variation, imagined by making substitutions when you're short an ingredient or two. When it comes to finding a mustard seed substitute, you may only have to look as far as your pantry. In a pinch, stone-ground mustard or whole-grain mustard can be used as a mustard seed replacement, tailoring your choice to the mustard's role in the recipe.
Mustard Seed vs. Ground Mustard
Mustard seeds and ground mustard are essentially the same thing other than their form. Mustard seeds are still in their shape, as they came from the seed pods of flowering mustard plants. Ground mustard, also known as mustard powder, is made by grinding up those same seeds.
Not all mustard seeds are the same, however. Brown mustard seeds are frequently used in pickling brines and in dishes such as corned beef, while yellow or white mustard seeds are often used to make the American version of mustard. The brown seeds are sometimes called Asian mustard seeds, as they're often used in Indian cuisine. These are quite pungent and taste hot.
White and yellow mustard seeds, which are the same thing, are larger than the brown seeds and have a milder taste. They may also be used in pickling spice blends. Black mustard seeds are quite small and less common than white, yellow or brown mustard seeds. They're also more pungent and hotter than the others.
Mustard's Role in the Recipe
The best sub for mustard seed depends on the role of the seeds in the recipe. When used as a pickling spice in liquid, for instance, the seeds' main role is to flavor the liquid, so its seed shape won't be missed when making a substitution. In such a case, ground or whole-grain mustards are sufficient substitutes, although they could cloud the liquid.
If the recipe relies on seeds for their texture and looks as well as flavor, such as in a homemade dressing for potato or chicken salad, dry mustard or some prepared mustards won't add texture, but they'll still taste great.
Mustard Seed Substitute
The simplest mustard seed substitute is simply a one-for-one replacement with whole-grain mustard. Since whole-grain mustard is full of mustard seeds, the recipe will still look, feel and taste much like it would if using mustard seeds on their own.
Ground mustard, also known as dry mustard, works well as a replacement when flavor is the goal rather than texture. This powdered mustard, when combined with a little liquid, is far hotter than an equal volume of mustard seeds, so start with just a pinch or two for every teaspoon of seeds called for in the recipe. Add more ground mustard to taste.
Using Prepared Mustard
If all you have on hand is prepared mustard, use only one-third of the amount called for in seed form. Since prepared mustards vary greatly from one to the next, you may have to adjust that quantity to achieve the desired flavor intensity. For instance, if the recipe is supposed to pack a wallop with its sinus-clearing heat, use whole-grain mustard, Dijon mustard or a takeout-style hot mustard. Hot mustard can be extremely hot, so use just a small dollop of it for starters.
Prepared mustard also adds a bit of liquid to the recipe, so if you are using a lot of it, cut back a little on other liquid ingredients if it could affect the consistency of a sauce or the finished dish. Prepared mustards also contain vinegar or another acidic liquid plus other spices that could slightly affect the recipe's flavor.