I could fill this page with the Science but boiled down...Cooked Herbs and Spices have a different and more intense flavor then raw spices. Conversely, that Raw flavor is not a bad thing, just different. Many people and entire styles of BBQ do both, rub at the begining and season at the end. This is the thought behind Memphis Dry Ribs. The formation of Bark is a combination of Caramelizing the Sugars, both natural and applied, and the browning of the Proteins called the Maillard Reaction. It has been tested and proven that these changes don't just change into " A " different flavor but change into Hundreds of different flavors. As mentioned above, throw a chunk of Pork or Beef in a Crock Pot, add water, veg and flavorings, you get a version of Pulled Pork or a Pot Roast...BUT...Brown off the same Meat and Veg over high heat, dry toast the Whole Spices before grinding and add all that to the Crock Pot and you get a whole different much better finished product...JJ
Here is a good balanced Rub that you can add what you like. The Turbinado Sugar holds up to a long cook and doesn't burn at temps under 325°F...
Mild Bubba Q Rub (All Purpose)
1/2C Sugar in the Raw (Turbinado)
2T Sweet Paprika (Hungarian)
1T Kosher Salt
1T Chili Powder (contains some Cumin and Oregano) Ancho Chile is same without cumin, oregano etc.
1T Granulated Garlic
1T Granulated Onion
1tsp Black Pepper, more if you like
1/2tsp Grnd Allspice
For more heat add Cayenne or Chipotle Pwd to taste, start with 1/2tsp and go from there. Makes about 1 Cup
Apply your desired amount of Rub to the meat, wrap in plastic and rest in the refrigerator over night.or longer. The day of the smoke, pull the meat out, add more Rub and go into your pre-heated Smoker...