Guinness Mustard

Ok, so we got this recipe out of the January Saveur (cheating, I know) but it is easy and excellent and we want to share it.
12 ounces of Guiness Stout (we used a draft can)
1 1/2 cup brown mustard seeds
1 cup red wine vinegar
1 tbsp. kosher salt (we used sea salt)
1 tsp. Freshly ground Black Pepper
1/4 tsp. ground cinnamon
1/4 tsp. ground cloves
1/4 tsp. ground nutmeg
1/4 tsp. allspice

Combine ingredients in nonreactive mixing bowl (we used pyrex) cover with plastic wrap and let sit for 1-2 days so that mustard seeds soften and the flavors meld. Transfer mixture into a food processor (We don't have one of those so we used a blender). And blend, stopping occasionally to scrape down the sides with a rubber spatula. Do this for about 3 minutes until the seeds are coarsely ground and the mixture thickens. Transfer into a jar and refrigerate over night and use immediately or refrigerate for up to 6 months.

Note: You probably won't want to eat this the next day as it is VERY intense when it is fresh. I recommend waiting a couple of days before you eat it. It is awesome then though.