In the culinary arts, the word spice refers to any dried part of a plant, other than the leaves, used for seasoning and flavoring a recipe, but not used as the main ingredient. Why not the leaves? Because the green leafy parts of plants used in this way are considered herbs.
Every other part of the plant, including dried bark, roots, berries, seeds, twigs, or anything else that isn't the green leafy part, is considered a spice. Today, India produces about 75% of the world's spices. They even created the Indian Insitute of Spices Research devoted to the study of spices.
Examples of Spices
These are all examples of spices. Note too that spices are used in dried form while herbs can be used either fresh or dried.
Tips for Cooking With Spices
One thing to keep in mind when cooking with spices is that spices start to lose their flavor when they are ground. So whenever possible, it's best to grind your own spices immediately before using them, rather than using spices that are already ground. You can use a coffee grinder or mortar and pestle for this purpose. If you do decide to use a coffee grinder you might want to use one only for spices and one for coffee beans so as not to accidentally flavor your morning brew!
Do spices expire?
While spices don't actually spoil or rot, they will lose their flavor over time. As spices are generally added precisely to add flavor, it is best to use them in a certain amount of time. If grinding your own spices isn't possible, try to use the freshest spices you possibly can. As a general rule, ground spices that are older than six months should be replaced. Whole dry spices can last for up to two years if stored properly.
How to Properly Store Spices
Spices last longer when stored in a cool, dry location. So keeping jars of spices right next to your stove will significantly reduce their useful life. An enclosed spice rack or storing them in an opaque container will help your spices keep their flavor longer.
Spices are used in small quantities to flavor dishes which means they add few calories to meals. This doesn't mean spices don't cause a large impact on your diet; they can be a great way to add necessary vitamins and minerals.
Spices in History
As the majority of the world's spices come from South East Asia, the spice trade helped drive the global economy starting in the Middle Ages. The Silk Road was a dangerous and long trade route that went from China to Europe. Sailing helped to speed up the shipment of spices. In search of a faster root to India, Christopher Columbus chose to sail east, landing in North America instead. It is believed that this mistake in continents is why Native American's were wrongly named "Indians."