Have you always wanted to start fermenting foods but you’re not sure where to start? Valerie O’Connor's recipe for fermented wholegrain mustard is perfect for beginners!

"I love wholegrain mustard and, when it appeared on the market many moons ago, I couldn’t get enough of its yummy, tart, sweet spiciness – especially on sausages or cheddar cheese. This works out a lot cheaper than those ceramic jars of wholegrain French mustard that I buy sometimes, though they are very tasty too." - Valerie O'Connor 

Makes 3 jars


  • 150ml whey
  • 100g yellow mustard seeds
  • 100g brown mustard seeds
  • 1 small onion, diced
  • 1 clove garlic, chopped1 tea
  • spoon sea salt
  • 2 tablespoons honey


1 Combine the whey, mustard seeds, onion and garlic in a bowl and leave it overnight – this will ensure the mustard seeds soak up the whey and swell up as they need to.

2 In a food processor or blender, whizz everything up with the honey and salt until you have a consistency that you like – not too smooth, you still want a few bits in it.

3 Spoon it in to your clean jars and ferment as the ketchup recipe above.

Tip: This will keep for months in the fridge.

Recipe and Photography Credit: Valerie O'Connor 

For more information on Fermentation, check out:

Fermented Tomato Ketchup

Fermented Beet Kvass