Unfortunately, like my vintage wheels, a seasoning s potency deteriorates with time. Consequently, dried herbs should be used within a year for the best flavoring, whereas dried ground spices will last about two years. Whole spices such as whole black pepper can be stretched to about four years. To keep your seasonings in tip-top potencies, you should store them in a cool, dry place. Tone Brothers recommend that you stack them in closed containers away from exposure to bright light, heat, moisture and dampness.
Heat can decrease the potency of the herb or spice.
Your spice rack should not be over the stove or near the disherwasher where steam and dampness can clump the heck out of it, a culinary frustration when you shake while you bake. Tone Brothers also recommends that you refrigerate red-colored spices such as chili powder, cayenne pepper and paprika, to prevent not only the loss of flavor, but also color. Oil-rich seeds, such as poppy or sesame seeds, also need to be stored in the refrigerator to prevent them from getting rancid. An airtight container can help keep the moisture out and the flavor and aroma in. Dried seasonings are convenient substitutions for fresh.