Most mustard is made from either white (or yellow) mustard plant, Brassica hirta. Its spicier cousin is the brown mustard, Brassica juncea. We use a combination of the two here. There is also black mustard (the spiciest of the bunch), but it is difficult to grow and is not very commonly found in the U.S.

The word mustard derives from Latin for mustum (fermented wine) + ardens (hot seeds).

Water revives the enzymes from dried/powdered mustard, and will create the pungency that mustard is known for. Interestingly, temperature affects the pungency too. Use cold water for a hotter mustard, and warm water for a more mellow mustard.

Conversely, acids slow this enzymatic process. So you can get mustard to a flavor you want (wait a few minutes or a few hours), then add brine/acid to “lock it in” by adding anĀ acid, (brine or vinegar).

Turmeric is what makes mustard yellow (not just by using “yellow” mustard) and is common in store-bought varieties.

Prep time: 
Fermentation time: 
Yield: 1 pint
  • 35g (3 oz. by weight) white/yellow mustard seeds
  • 35g (3 oz. by weight) brown mustard seeds
  • 40g (about ½ cup volume) white/yellow mustard powder
  • 4 cloves garlic
  • ¼ cup (60ml) pickle brine or liquid whey
  • 4 teaspoons sea salt
  • 7 fl. ounces (205ml) filtered water
  • 2 Tbsp. (30ml) (40g) honey (OPTIONAL)
  • 2 tsp (10ml) turmeric powder (OPTIONAL)
  1. Add brown and yellow seeds, water (colder water for spicier, warm water for more mellow) and garlic cloves in a food processor or blender. Mix about 6-8 minutes
  2. Add mixture to a clean wide mouth pint mason jar.
  3. Add mustard powder. To achieve a mellower/less spicy mustard, wait 10 minutes before adding remaining ingredients.
  4. Add salt, turmeric, honey (if using) and pickle brine to jar.
  5. Stir well.
  6. Tightly secure lid and ferment at room temperature 3 days.
  7. Store in refrigerator for up to a year.