Step 1

Mix the mustard seeds and beer together in bowl, cover and set aside overnight. (The mustard seeds will soften and soak up most of the beer.)

Step 2

Sterilise the jars for the mustard. Wash in very hot water or on the hot cycle of a dishwasher. Preheat the oven to 160C/325F/Gas Place the jars upside down on a baking tray and dry in the oven for 10-15 minutes.

Step 3

Stir in the remaining ingredients, then blend in a food processor until nearly smooth (you may need to do this is batches).

Step 4

Spoon the mustard into the sterilised jars; tap gently to remove all the air bubbles.