We make our mustard with brown and "Oriental" golden mustard seeds, using a recipe we got from a stand at the Royal Agricultural Winter Fair in Toronto in 1998. We'll never buy commercially made mustard again.
Grainy mustard is fabulous with roast ham; it's equally good in beet salad, with steamed green beans, in salad dressings, on hamburgers, etc. etc.
The last time we bought a jar of mustard was at a moutardier in Charroux, "un des plus beaux villages de France". The mustard made there was spectacular and we had to buy a jar. We had no idea until we got home that it is particularly sought out. (See http://www.france-voyage.com/tourism/charroux-mustard-1776.htm)
We kept our little jar; we couldn't bear to throw it away. Now it holds face cream....
Charroux mustard ingredients: Vinaigre de vin blanc, eau, graines de moutard, vin de St-Pourçain, sel, épices, antioxydant #360 (Best before 21 Sept 1999)