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. 

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:

Back to Basics with Fermentation

Fermented Tomato Ketchup

Fermented Beet Kvass