Can one have too many mustards? I think not. This was simple, tasty recipe that I found somewhere on the interwebs, but I can't recall where.
Soak the mustard seeds with beer in the refrigerator for 24 hours. If it soaks up too quickly, add more beer.
Transfer soaked seeds to a food processor, along with the garlic, apple cider vinegar, brown sugar, salt and pepper. Pulse until desired consistency. I prefer a thicker, stone ground style mustard.
Pack the mustard into hot, sterilized jars, filling up to ¼ inch from the top. Run a spatula along the walls to release air bubbles. Wipe the rims of the jars before lightly screwing on the lids.
Refrigerate the jars for 2 weeks before using.