Smoked Fermented Seeded Mustard
Prep time: 15 mins | Fermentation: 3 weeks | Mellowing: 1–2 weeks| Total: 4-5 weeks.
Serves: 1lt End Product
Ingredients
- 260g yellow mustard seeds
-260g brown mustard seeds
- 620g filtered or spring water
- 80g raw apple cider vinegar
- 80g sauerkraut juice (or whey)
- 40g verjuice (or a sharp white wine like Riesling or Sauvignon Blanc)
- 15g honey (smoked honey is excellent if available)
- 12g smoked salt
- 12g cooking salt (non-iodised)
- Extra honey, salt, and apple cider vinegar to taste (for final adjustments)
Special Equipment
- 1.5L fermenting vessel with a swing-top lid or removable air tight lid
- Stick blender (immersion blender)
Method
1. Combine Seeds: Place both the yellow and brown mustard seeds into a sanitised fermenting vessel.
2. Mix the Liquid Base: In a small bowl, whisk together the apple cider vinegar, sauerkraut juice/whey, verjuice, and honey until the honey has completely dissolved. Pour this over the seeds.
3. Prepare the Brine: Weigh the water into a jug. Note on Temperature: Use cold filtered water if you prefer a fiery, sinus-clearing mustard. If you prefer a more mellow, seeded flavour, use room temperature or slightly lukewarm water (around ) to help temper the mustard's natural heat.
4. Incorporate: Use chopsticks or a long stirrer to mix the contents thoroughly for at least 30 seconds, ensuring you reach into the bottom corners of the vessel.
5. The Ferment: Label your vessel and seal the airtight lid. Place it in a dark spot in your kitchen. For the first week, open the lid and stir the mixture twice daily.
6. The Wait: After the initial week of stirring, let the mustard sit undisturbed in its dark spot for a further two weeks (three weeks total fermentation time).
7. Blitz and Balance: Stir the mixture well. Using a stick blender, pulse the mustard until roughly 50% of the seeds are broken down. Taste the mustard and adjust with extra salt, vinegar, or honey if desired(Noting it will be spicy and almost metallic right now, so don't go too hard!).
8. The Mellowing Phase: Wipe down the inside walls of the vessel to keep it tidy. Seal the lid and let it rest in a cool, dark place for another 1 to 2 weeks. Taste at the one-week mark to see if the flavours have mellowed to your liking.
9. Store: Once you are happy with the flavour, transfer the mustard into sanitised, labelled jars. Store in the refrigerator.
Serving Suggestions
Now that you’ve crafted the perfect jar of mustard, here are a few of my favourite ways to use it:
- The Ultimate Ham & Cheese Toastie: Slather a generous layer of this mustard onto thick-cut sourdough. Layer with premium leg ham and a sharp Australian cheddar or Gruyère. The acidity of the ferment cuts through the rich cheese perfectly.
- Mustard & Garlic Roast Chicken: Mix two tablespoons of your seeded mustard with minced garlic, softened butter, and a pinch of thyme. Rub it under the skin of a whole chicken before roasting for a golden, flavour-packed crust and incredible pan juices.
- Elevated Curried Eggs: Give your curried egg mix a texture upgrade. Fold a teaspoon of this mustard into your mashed yolks with a touch of kewpie mayo and curry powder. The "pop" of the mustard seeds takes this nostalgic snack to a gourmet level.
- Mustard-Based Dressings: Instead of a heavy mayo dressing, whisk this mustard with extra virgin olive oil and a splash of nice vinegar. Toss through warm boiled potatoes and fresh chives for a bright, zesty side dish.
Tips, Troubleshooting & FAQ
1. The Power of Smoke:
While you can use standard salt and honey, the smoked elements add a sophisticated layer of flavour that makes this mustard stand out from the rest. For the salt, I highly recommend Olsson’s Red Gum Smoked Salt. Smoked honey can be a bit harder to come by, but your local BBQ store or even online can help you out.
2. Water Quality:
Always use filtered or spring water. Chlorine in tap water can sometimes inhibit the fermentation process.
3. Why "non-iodised" salt?
Iodine is often added to table salt to prevent deficiencies, but it can inhibit the growth of the good bacteria we want in a ferment. Stick to your Smoked Salt or a good quality Sea Salt/Kosher salt for the best results.
4. Why such a large batch
While this recipe makes a generous amount, keep in mind that seeded mustard lasts almost indefinitely in the fridge and, much like a fine wine, actually improves and ages with time. Given the total process takes about a month and a half, it makes sense to produce a substantial supply. If you find you don’t use it quite that often, it makes a wonderful gift when jarred up in smaller portions, or you can simply halve the recipe.
5. My mustard looks very dry, has something gone wrong?
Mustard seeds are incredibly thirsty! They will soak up a lot of the liquid in the first 48 hours. As long as the seeds look damp and there isn't a hard crust on top, you are fine. If it looks completely parched, you can add a splash more filtered water with a tiny bit of salt, but usually, the "blitzing" stage releases enough internal moisture from the seeds to create that perfect mustard consistency.
6. How do I know if it’s fermenting correctly?
Because mustard seeds are naturally antimicrobial, you might not see as many "bubbles" as you would in a jar of sauerkraut. However, you should notice a slight change in smell, from sharply pungent to something more complex and tangy. The "burping" of the jar when you stir it twice a day in the first week is the most you'll need to do for this ferment and you'll only notice small bubbles.
7. It tastes really bitter or "hot" after the first 3 weeks, is it ruined?
Not at all! Freshly crushed mustard seeds contain enzymes that create a very intense, almost bitter heat. This is why the mellowing phase (the final 1–2 weeks) is so important. Time and acidity are what "tame" the mustard. If it’s still too sharp, leave it in the fridge for another week; it will continue to mellow slowly over time.
8. There is a white film on top, is it mould?
Giving mustards, natural antimicrobial properties, this will be quite rare, but If you see a thin, white, opaque film on the surface, it is likely Kahm Yeast, which is harmless. Simply scrape it off and proceed. However, if you see fuzzy growth that is green, black, or furry, discard the batch. To prevent this, always ensure your stirring implement is sanitised and if in a warm climate, you can add a layer of cling wrap to the top of your mustard to help omit the kahm yeast. It's important to make sure your ferments are in a spot where the temperature is as consistent as possible. Heavy fluctuations in temperature can encourage unwanted or harmful micro-organisms.
The Master Plan: When to Start Your Batch
Since this fermented mustard requires a minimum of 5–6 weeks to fully develop its depth and mellow out (3 weeks fermenting + 2 weeks mellowing + 1 week buffer), timing is everything. Whether you are prepping for a holiday feast or planning some home-made gifts, use this "Start By" guide to ensure your mustard is at its absolute peak for these special dates:
| Occasion | Event Date | Start Your Batch By |
| Easter (2026) | 5 April 2026 | 22 February 2026 |
| Mother’s Day | 10 May 2026 | 29 March 2026 |
| Father’s Day (USA) | 21 June 2026 | 10 May 2026 |
| Father’s Day (AUS) | 6 September 2026 | 26 July 2026 |
| Thanksgiving | 26 November 2026 | 15 October 2026 |
| Hanukkah (Starts) | 4 December 2026 | 23 October 2026 |
| Christmas Day | 25 December 2026 | 13 November 2026 |
| Lunar New Year (2027) | 6 February 2027 | 26 December 2026 |
| Valentine’s Day (2027) | 14 February 2027 | 3 January 2027 |
What do you plan to use your mustard in? Do you have any feedback or questions for this recipe? Feel free to leave a comment and we can have a chat about it all.