we use Keen's dry mustard in a can:
For over 250 years, Keen's has provided premium quality Dry Mustard to discerning customers around the world. The brand was first manufactured and sold
in 1742 by Messers Keen and Sons in the Garlick Hill section of London, England
. Keen's quickly established itself as a superior mustard, winning prestigious medals in London, Paris, Moscow, Australia
and Philadelphia while also obtaining royal warrants to William 1V, Queen Victoria and Napoleon III. Today the tradition continues. Keen's Dry Mustard is manufactured by Colman's of Norwich by appointment to Queen Elizabeth II, and remains the "genuine double superfine" grade. Insist on the very best. Use Keen's Dry Mustard.