Spicy Brown Mustard

I have gotten interested lately in cooking. And one of the things I've been doing is making lots of things we normally buy from scratch. I've dabbled with butter, mayonnaise, salsa and even ketchup. Some successes and some not. Today I made a jar of spicy brown mustard. I found a simple recipe in Mark Bittman's cookbook "How to Cook Everything". I really enjoy this cookbook. The recipe is simply brown mustard seed, rice vinegar, yellow mustard powder, salt and a little water. Its in the fridge and will need to sit overnight before a good taste can be had...