Soak the mustard seeds and caraway seeds in the beer overnight.

When ready to make the mustard, combine the soaked seeds with the remaining ingredients in a blender or food processor (for a whole-grain mustard you can reserve two tablespoons of the mustard seeds to stir in later, if desired).

Blend in the blender or food processor until desired consistency is reached.

Stir in reserved mustard seed, if desired.

Transfer to a glass jar and cover.

Let sit on the counter for three days.

Pop in the fridge and enjoy!