Dijon Mustard

Combine both mustard seeds, white wine vinegar, white wine, shallot, and bay leaf in a glass jar or bowl. The seeds must be completely submerged in liquid. Cover and let soak at room temperature for 48 hours — the seeds will swell dramatically, absorbing most of the liquid, and the liquid will turn from pale yellow to a cloudy, mustardy gold. This soaking is essential: it begins to activate the myrosinase enzyme that converts glucosinolates into the pungent isothiocyanates that give mustard its heat, and the acid sets the color to pale yellow.

Remove the bay leaf. Transfer the soaked seed mixture to a blender. Add the salt. Blend on high for 2–3 minutes for a smooth Dijon-style mustard, or pulse just 8–10 times for a grainy whole-seed style. The emulsification is important: the longer you blend, the more the seed hulls break down and release their oils into the liquid, creating a cohesive emulsion. Scrape down the sides regularly. Add a tablespoon or two of cold water if the blender is struggling — the cold water also reduces the enzyme temperature, preserving more heat.

Transfer to a sterilized glass jar. Cover and refrigerate for at least 24 hours before using — the mustard needs time to mellow, for the sharp, raw edge to round out, and for the emulsion to stabilize. Freshly blended mustard is fiercely hot and somewhat bitter; after 24 hours it becomes more complex and cohesive. After 3 days, it is at its best. The mustard keeps refrigerated for 3 months. The heat will gradually diminish over time as the isothiocyanates degrade.