In my mind, ground and whole mustard does not taste like the yellow stuff in the plastic bottle. Maybe if you added vinegar and salt?
I add some of both to summer sausage. Wet your finger, touch it to the pure spice and taste it. Which is a good idea for all spices. Taste them pure. That way you get a sense for what it tastes like and can notice it.....even mixed in with the other stuff.
In Rytek's book, he mentions that once you get a sense for what individual spices taste like, you can almost tell how much of what is in a sausage, just by tasting it (the sausage).