Fermented Honey Mustard

What You'll Need

  • measuring cups and spoons
  • small jar or non-reactive container
  • Cheesecloth or paper towel
  • food processor or blender
  • good kitchen knife and clean cutting surface
  • spatula or silicone spoon
  • small clamp-top jar for storage
  • 5 Tbs yellow mustard seeds, or a blend of brown and yellow seeds
  • 3/4 tsp fine sea salt, divided
  • 1/2 cup mild kombucha
  • 1 garlic clove, minced fine
  • 1 Tbs honey
  • 1 tsp olive oil

This is such an easy, delicious way to make the tangy flavor of homemade mustard come alive in your kitchen. A complex layering of flavors belies the simplicity of the process. Spike the flavor up with some finely grated horseradish, or ginger, or chili, if you like. Once you have the basics down, there’s room to tinker. We call for a mild kombucha, such as one made with white or green tea, but use a mild black tea kombucha if that is what you have at hand. The tannins in black tea, combined with the natural bitterness of the mustard seed, can be a bit of a heavy combination, but some folks like mustard with a punch, so use your judgment. Here, we used a green/black tea kombucha blend, seasoned with turmeric, ginger, allspice, and cinnamon, but a plain variety would work as well; so much flavor comes from the mustard seeds.

Ah, the mustard seeds! As you may know, mustard seeds come in several colors and flavors. The yellow seeds are the most versatile and balanced, not too bitter or too hot but full of flavor nonetheless. The black/brown varieties can be a bit more acrid or piquant; use them in this recipe blended with the yellow seeds if you want to ramp up the intensity. You can also sometimes find hot mustard seed, aka Chinese mustard, although it is less widely available; it is smaller, hotter, but generally less complex a flavor than the yellow. Use it in conjunction with the yellow seeds, if desired.


Put the mustard seed in a sterilized jar and add a pinch of sea salt, no more than 1/4 tsp.
Pour the kombucha over the seeds, adding a bit more if necessary to ensure they are covered. Stir well.
pour kombucha over seeds
Cover loosely with cheese cloth or a paper towel and leave in a warm, dark place for a week to ferment, as if it were kombucha.

After the week is out, the seeds can be use whole, sprinkled in stir-fry, curries, or over roasted meats and veg. Their texture has softened, and the natural pungency of the raw seeds has relaxed somewhat.

To make the honey mustard, blend the fermented mustard seeds in the small bowl of a food processor or blender.
pour into blender
Add the minced garlic, 1/2 tsp fine sea salt, and honey. If there is liquid left in the jar after soaking the mustard seeds, it can be used to add liquid to make the seeds blend together more easily. Pulse until the desired consistency is reached. We like it blended well, with a smattering of whole seeds left, to add mouthfeel and interest.
add other ingredients
Pour the mixture into a storage jar with a lid, scraping down the blender with a spatula or silicon spoon to get out all the mustard.
scrape blender and add to jar
Add the olive oil to the mustard mixture and stir well to combine.
add olive oil
Store the fermented honey mustard in a lidded jar in the fridge, where it will keep for at least a month. This recipe is not shelf stable. 


Over to You

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