11 ½or 12 ounce bottle of Guinness Stouteither draught or the standard bottle will work here. I prefer drinking the draught but in the mustard the taste difference is slight
1tspground or 12 whole peppercorns
¼tspground or 5 whole cloves
¼tspground or 4-5 whole allspice berries
Combine all ingredients in a non-reactive bowl or glass jar and allow to sit, covered for 24-48 hours. This lets the mustard seeds and other spices to soften and the flavors to meld.
If using whole spices they will generally float to the top. When it is time to mix it all up add as many as you can gather of the spices to the food processor first, along with about a quarter cup of the mustard seeds and some liquid. Process until no large chunks of spices are visible and the mixture is almost creamy, about three minutes.
Add the remaining seeds and liquid and continue to process to your desired consistency, about another two or three minutes.