• Andrea K. Marcinkus

Fermented Mustard

I made a mistake.

I was looking for a new source for spices and decided to explore a few brands that were available on Amazon. I was looking for bulk buys, in small-ish quantities to refill my jars and keep a little extra in storage. The thing is, as I was shopping, I noticed that the next size up in bulk bags was often just a few dollars more.

"I will get the next size up," I thought. "I can always share with my friends, family, and neighbors."

And this was my mistake.

I clearly had no idea what 1 lb or 3 lbs of mustard seed looks like. In case you are wondering yourself, here you go:

Yes, those are quart-sized (not pint sized) canning jars. And that box of Diamond Crystal? Yeah, 5 lbs. THAT is how much mustard seed I bought.

So, what does one do with this much "eye of newt"? (Yes, "eye of newt" is a European folk-name for mustard seed.)

I thought about acting out the witch scene from Macbeth:

Eye of newt, and toe of frog,

Wool of bat, and tongue of dog,

Adder’s fork, and blind-worm’s sting,

Lizard’s leg, and howlet’s wing,

For a charm of powerful trouble,

Like a hell-broth boil and bubble.

Or maybe translating those ingredients into a modern elixir made with these herbs? "Eye of Newt" is a folk name for Mustard Seed, (Brassica nigra). "Toe of Frog" refers to a type of buttercup.  "Tongue of Dog" is Hound's Tongue (Cynoglossum officinale), a plant that has some toxic properties that mainly affect cattle and horses.  "Adder's Fork" is a fern more commonly known as Adder's Tongue (Ophioglossum vulgatum) and is useful for aiding the healing of wounds and bruises. And that is as far as I got with my Googling skills before realizing that, perhaps, this was not the best way to spend my time during "safer at home." This "charm" couldn't turn into a cleaver cocktail. (Clearly this quarantine is getting to me!)

So, why not make that tasty condiment, mustard?! But it didn't feel right just finding a recipe, popping it into the Vita Mix blender with salt and vinegar. If you follow my blog and social media, you know how much I love naturally fermented foods. So why not try fermenting mustard seeds?

That mistake? Mistake no-longer. THIS is the BEST mustard I have consumed. I have also given some to my friends and they agree - 4 people ate a half of a pint-jar of this stuff in one sitting!

So I got out my fermentation equipment and started. I made A LOT of mustard. The recipe at the end of this post is for one quart jar (a sane amount of mustard for a family), I did make two quarts, as you will read, but I did a little experimenting in the process. (Gosh, I hope my neighbors like mustard, because everyone is getting some.)

I knew the mustard seeds would be cleaned, and wouldn't have any natural bacteria on them to ferment in the brine. I would need to add something to the fermentation vessel to help it get going. In one jar, I added non-pasteurized apple cider vinegar (with the mother - a brand like Bragg's does the trick). In the other, I added a few tablespoons of naturally fermented sauerkraut I had in my fridge.

Air lock fermentation kit.

I sterilized 2 quart jars and the fermentation air-lock lids that you see above. You can get these from Amazon or a specialty retailer or a wine/beer brewing store. You don't need the air locks- you could use the cheese-cloth method that I used in my ramp "kimchee" blog.


I didn't think that the seeds would ferment by just sprinkling with salt and adding water afterwards - I also wanted to control the salinity level. So I made brine using a ratio of 2.5 cups of distilled water to 4 tsp of salt (I used Kosher, but you could use pickling or sea salt). It has to be distilled water so there are not any additives to it. Alternatively, you could boil water for 10 minutes and let cool to room temperature. I always make extra brine, and I made 4 batches at this ratio.

I poured in half brown mustard seed and half yellow to my clean jar - one cup each. I poured the brine over, until the seeds were covered by at least a 1/2 inch of the brine. Then, I added 2 TSP sauerkraut juice to one, and 2 TSP of apple cider vinegar to the other. I put on the lids and waited.

A few hours later, I realized I did not add nearly enough brine. I didn't consider that the seeds would swell so much as they absorbed the moisture. I was happy that I had that extra brine, so I added it until half-way full. Overnight they took on more fluid, and I ended up filling the jars to 2 inches from the top.

After a few hours of soaking in the brine.

Almost there, but still needed to add more brine.

Then I waited. After 2 days, bubbles started to rise when I wiggled the jars a bit. (Yes, I DID have to quote Shakespeare's witches again: "Double, double toil and trouble;Fire burn and cauldron bubble!") After five days, the bubbling slowed, and I tasted the seeds. The one with the apple cider vinegar was sour and biting with salty tang. The one with the 'kraut juice was less sour and just slightly bitter, but not unpleasantly so. The both had the complexity of fermentation. I waited 2 more days before I decided to give them a whirl in the blender.

Drained, fermented mustard seeds

I drained the first batch of seeds with a colander over a bowl. I wanted to use some of the fermentation liquid to blend the seeds. I popped them into the blender, added about a 1/4 of the fermentation liquid, and tasted. It was really dry, and not as sour as prepared mustard should be. So I kept adding apple cider vinegar until it was the correct consistency in the blender. I wanted some of the grainy texture, and so I stopped my blending at the consistency you see below. The flavor was a like a high-quality whole-grain German-style mustard. Amazing!

I packed half of this into jars, and decided to make a more smooth American style yellow mustard with the rest. I added a teaspoon of turmeric and a 1/2 teaspoon of sweet paprika, a little more vinegar, and blended until most of the texture was gone. This style is great on hot dogs and knockwurst.

I followed the same procedures for the the sauerkraut sourced ferment. However, I was surprised that this mustard was not as sharp and peppery as the apple cider vinegar one, so I added some white wine vinegar instead. This mustard turned out to taste like French-style mustard. So after putting some of the plain variety into jar, I added dried tarragon from last year's garden to the rest.

All the jars of mustard could use a little rest in the refrigerator to help mellow the sharpness and blend the flavors, although we started eating it after just a week of rest.

All the varieties yielding from 4 cups of dry mustard seeds.

I made a mistake. Such a happy mistake. I don't think I'm ever going back to store-bought mustard again.!

Here is my adapted recipe from the lessons learned above, in case you would like to give it a try. This uses 2 cups of mustard seeds in a quart-sized jar.

Fermented Mustard

5 cups of distilled water

8 tsp of salt (I used Kosher, but you could use pickling or sea salt)

2 cups dried whole mustard seeds (yellow, brown, or a mix of both)

1-2 TBS apple cider vinegar (with the mother) or unpasteurized fermentation juice (like pickle or sauerkraut brine)

1-2 cups of vinegar (your choice of type, but you might want to avoid the regular white stuff - it can be really harsh. Try apple cider, white wine, red wine, champagne, or malt vinegar)

1. Clean and sanitize your fermenting vessel and equipment.

2. Make a brine with the water and salt in a separate jar. Shake to combine. You will have extra, just in case.

3. Add 2 cups of mustard seeds to the vessel and add 1-2 TBS apple cider vinegar or fermentation liquid.

4. Add the brine to no more than 2 inches to the top of the fermentation vessel. You want to make sure there is enough liquid for the seeds to hydrate, but not so much that you will cause it to spill over during the fermentation stage.

5. Put a fermentation lid or cloth cover on your jars, and wait. Keep an eye on the fermentation to make sure that the seeds are completely covered with brine. Add more if needed.

6. Depending on how warm or cool the room is where your fermentation is taking place, timing can vary. After the 2nd or 3rd day, taste your fermenting mustard to see how sour it is. Keep fermenting the mustard for at least 5 days, or longer if you would like. When you like how it tastes, move onto step 7. (Know that you will be able to make it more sour by blending it with vinegar in the next step.

7. Drain your seeds, catching the fermentation brine in a bowl. Add the seeds to a blender (or reserve some for adding in as whole seeds later), and add about 1/4 to 1/2 of the brine. Start blending.

8. Go slow and taste as you go. Start adding about 1/2 cup of the vinegar and taste. If it is too thick, and too flat, add more vinegar. If it needs more salt, add more of the fermented brine. Keep going until you like the texture and taste.

9. Feel free to add in other herbs and spices to the mix. Try 1 tsp turmeric and 1/2 tsp paprika for an American yellow mustard, 1/2 TBS dried tarragon, or t tsp black pepper for variation.

9. Pack into sterilized jars and store in the refrigerator. It will last about 4-6 months in these jars. This is still a living fermentation, since we didn't water-bath can the mustard, so make sure the lids are on loosely to allow some gas to escape. (If you needed the mustard to be shelf stable, you could water-bath can them, but you would loose the probiotics in the live ferment.)

10. Allow to rest at least 2 weeks for the flavors to mellow.

Recent Posts

See All