Mustard seeds
Use when you want a whole-grain, crunchy texture. The three types are yellow, aka white (Sinapis alba), the mildest and used mainly in American-style mustards and for pickling; brown (Brassica juncea), zestier and used in European-style mustards (like Dijon), for pickling, and in Indian cooking; and black (B. nigra), also used in Indian food; they’re interchangeable with the brown. Seeds need to soften in liquid for 1 to 2 days before you make mustard with them.
Mustard powder
For silky smooth mustard. It’s nothing more than ground mustard seed, and the most common brand is Colman’s, a blend of brown and white seeds. Mix it with liquid (like water or beer) and let sit overnight to hydrate and develop flavor. Don’t let it sit longer, though, or it will taste harsh.
How long does homemade mustard keep?
All are fine for at least 2 weeks, covered and chilled airtight. The flavor stays the same, but some mustards get a little thicker (whisk in a tiny bit of water to loosen it back up).
Boost flavor with mustard in these recipes:
Indian potatoes with black and yellow mustard seeds (left)
Grilled chicken Dijon
Deviled eggs with smoked salmon and two mustards