How to Make Fermented Mustard (Recipe)

When I was young I remember teachers saying they didn’t pick favorites.  They’d swear that all the kids were equal but different and each had a special place in their heart.  I could say the same thing about my recipes – but I’d be lying.  Some things just work out better than others.  And I’m crushing a little inappropriately on fermented mustard.

If you’ve never made anything fermented before, this is a great place to start.  If you’re unsure of the term lactofermentation, check this out.

How to Make Fermented Mustard (Recipe) Whey Preserving Recipes Mustard

The final product is spicy (almost at a horseradish type of heat), sweet and sour.  It’s thicker than store-bought mustard (my seeds were  still fairly coarse after grinding); you could thin it out with more water but I love the consistency and texture that comes from all of these fermented bits.

As far as taste, there’s an underlying sour that can only come from fermentation (think of  kosher deli pickles as opposed to those made in vinegar).  It’s full of flavor and it will continue to improve over the coming weeks even though it’s ready to eat now.

I fermented it with an airlock (that link tells the story) but you could likely get away with a lid though pressure will build up in the jar over the first few days if it’s not vented.  If you don’t have access to an airlock, you could use a balloon like Kaela from Local Kitchen describes here.

How to Make Fermented Mustard (Recipe) Whey Preserving Recipes Mustard

I really hope you’ll make this.  And I really hope you’ll let us know what you think!


  • 0.5 cups of whole mustard seed
  • 0.25 cups of water (if your tap water is chlorinated it’s essential you leave the water in a large bowl for about an hour to let the chlorine evaporate or it will hamper fermentation)
  • 2 tablespoons whey (it’s a bi-product from making Greek Yogurt)
  • 1 teaspoon salt
  • juice of 1 lemon
  • 2 garlic cloves, chopped fine
  • 2 tablespoons honey
  • 0.5 dried hot pepper (optional)


  1. Using a coffee grinder or a mortar and pestle, crush the mustard into powder.
  2. Mix all ingredients in a bowl (this keeps the sides of the jar clean)
  3. Using a jar funnel, pour the mustard into the bottom of a clean jar.
  4. Place airlock on top and leave the jar in a warm place for 3-4 days (the top of a cupboard is great as it’s out of the way and heat rises).
  5. You can eat at any time from this point onwards though the flavor will continue to develop; put a lid on it.  Placing it in the fridge will slow fermentation and leaving it on the counter will allow the process to continue which is good – until a point (that point, specifically, is mold).

There’s not much to it – but it’s a condiment that’s unlike any you’ve ever had.  It may, in fact, be the Teacher’s Pet.

Leave a Reply

  1. Wow. I don’t even know what to say. I would never, ever have thought to ferment mustard–but now I absolutely want to! I bet the sandwiches are EPIC.

  2. My mason jar-sized rubber stopper has arrived and I’m excited to try this! Quick question: are you using yellow or brown mustard seeds in this recipe? I tried making a different mustard recipe recently with brown, and the results were…well, not edible, but I’m not sure if that was related to the seed type or user error. Thanks!

    • Molly,

      Thanks for the comment and I’m so super excited you’re trying this. It’s one of the best things we’ve made in a LONG time. I do hope you’ll let us know what you think; I’m finding it gets better with time – but have loved it from the start.

      We used yellow but it was just because that’s what we had. Now you have me curious about brown. :)

      Let us know how it goes!

    • Hi Emsenn!

      It’s written a little less than clear – I used half of a dried pepper ried pepper – though you really could use as much as you want to taste… :)