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

The well-known spicy condiment is made from the seeds of either the white (aka yellow) mustard plant (Brassica hirta), and/or from its spicier cousin, brown mustard (B. juncea). We use a mixture of the two seeds for this recipe. There is also black mustard (B. nigra),  the spiciest of the bunch, but it is difficult to grow and is not commonly found in the U.S. (except, interestingly, wild in California, as it was planted by early Spanish settlers!)

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 “lock it in” by adding an acid (e.g. pickle 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: about 1 pint
  • 35g / 3 Tbsp. white/yellow mustard seeds
  • 35g / 3 Tbsp. brown mustard seeds
  • 40g (about ½ cup) white/yellow mustard powder
  • 4 cloves garlic
  • 30 ml / 2 Tbsp. pickle or sauerkraut brine, or plain kombucha
  • 15 ml / 1 Tbsp. sea salt, plus more to taste
  • 175 ml / 6 fl. ounces filtered water
  • 40g / 30 ml / 2 Tbsp. honey (OPTIONAL)
  • 10 ml / 2 tsp. turmeric powder (OPTIONAL)
  1. Add brown and yellow seeds, garlic cloves and water (colder water for spicier, warm water for more mellow) to a food processor or blender. Mix for 6-10 minutes, until the liquid becomes mucilaginous.
  2. Add mixture to a clean pint sized or larger glass jar.
  3. Mix in 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.




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