Most herbal flavors and aromas are released by heat. Although fresh herbs are usually preferred, dried versions can be used. When possible, grind whole spices in a grinder or use a stone mortar & pestle just prior to using for enhanced flavor. Toasting or dry roasting whole spices in a dry skillet over medium heat before grinding will bring out even more flavor. A good rule of thumb is to substitute 1 teaspoon of crumbled, or 1/4 teaspoon powdered, dried herbs for each tablespoon of fresh herbs called for.