I'm just curious, is there a reason you are wanting to use the dry in place of prepared mustard? Actually once you mix the powder with a liquid, you are in essence making a prepared mustard. You stated that is was too hot and pungent, what was the ratio of your substitution? In most cases, the dry is equivalent to 1/3 of the prepared. So for each cup of prepared mustard you would use 1/3 cup powdered, or for each Tbs use 1 tsp. It also depends on how you mixed and prepared your sauce. Coleman's powder is a mix of yellow (mild) and brown (not so mild) seeds, and if you mixed it using cold liquids and very little acid then what you made was essentially a "hot" mustard. Mustards prepared using a powder will be less pungent if you 1) Use a powder made from all yellow seeds 2) Mix the powder with something acidic 3) Make sure the liquid you use is hot. Try tasting your mustard powder on it's own. It doesn't have much of an impact until it's mixed with a liquid. Both acid and heat in the liquid will lessen the pungency. Dijon is more pungent than regular yellow mustard because it's mixed with a lower acidic liquid, white wine vs vinegar. Also, the mustard will mellow the longer it sets. Oh yeah, and if I remember correctly, the Plochman's mustard you normally use is pretty mild so that may be another reason you weren't happy with the results of your sauce. I'm interested in the results of your trials, keep us updated!