Fresh spices, herbs and blends should always be near at hand when you're cooking. But this definitely doesn't mean you should store them right by the stove. In fact, that's one of the worst places in the kitchen to keep your precious seasonings — the heat will age them quickly, making them stale before their time. The same goes for the microwave and toaster. Herbs and spices should always be stored well away from heat and sunlight, ideally in a closed cabinet or a wall rack that doesn't receive direct sun.
Air and moisture are also enemies of freshness, so make sure your spice cabinet is dry and that all your containers are tightly sealed. Keep them away from humid sources such as sinks, dishwashers, kettles and coffee makers, and reseal them quickly when you have them out for cooking.
If you purchased seasonings in thin plastic bags, it's a good idea to transfer them to sturdier glass containers so that they remain potent. This is especially important for ground spices and herbs, which release their volatile oils more readily than whole ingredients. You'll want those flavors in your food, not seeping out through flimsy packaging.
Herbs and spices are usually sold in small quantities, so they can be used up before their flavors fade.The best storage temperature for these is one that is fairly constant and below 70° F.
I store larger amounts in tightly sealed containers in the refrigerator. As long as your bulk spices are well-packaged to prevent moisture from getting in, they will last up to three years! But fluctuations in temperatures will cause condensation and eventually mold, so if you store spices in the freezer or refrigerator, be sure to return them after use.
For the very freshest flavors and aromas, you can grind your spices at home. All it takes is a small coffee mill, salt grinder or peppermill. Make sure to clean the grinder thoroughly after each use so the volatile oils don't linger and grow stale, tainting the next fresh batch you prepare.