Ever wonder just how fresh those spices are sitting in your cupboard? If you're cooking with some spices bequeathed to you in your Grandma's will, you might as well be cooking with sawdust.
Spices, like all organic material, are plagued by the law of entropy which, simply stated, means "everything breaks down." The trick is to find out how to slow down entropy in your spice drawer or rack. To do this, you must identify the three principle enemies of herbs and spices:
Light - We all know that leaving fabric in direct sunlight will eventually fade and damage it. Light has the same effect on dried organic material, such as herbs and spices.
Humidity - Water plays an important role in the decomposition of organic material. For example, in the field of archaeology, it is well-known that artifacts are best preserved if they are either perfectly dry or completely wet. This rule applies as well to the contents of your spice bottles.
Air - Although we couldn't possibly live without it, air provides the fuel for the vast majority of chemical reactions we experience. The oxygen it contains combines well with a wide range of chemicals, including those in herbs and spices. When the chemicals recombine, the original material breaks down, destroying the flavor we want in our foods.
Before we can be confident of how to preserve herbs and spices, it is helpful to understand just what we are preserving. Spices and herbs used for cooking contain chemical substances called terpenes, commonly known as essential oils. These essential oils are what provide the characteristic smell or taste of herbs and spices. Without them, we are left with something that tastes no better than grass clippings from the lawn.
Keep it in a Cool, Dry and Dark place -- The best environment is cool and dry. Cool temperatures reduce chemical activity. Dry conditions reduce the presence of water and its decaying effects. Do not store them over your stove or oven!
Even with the best preservation methods, herbs and spices eventually lose their flavor. When should you throw them out? Let's begin with some time limits.
The following are general shelf life guidelines when the herb or spice is under ideal conditions:
Look - Take a good look at the contents of the jar. Is it faded? Do the contents cake together? Are there suspicious signs of insect inhabitants? If you answer "yes" to any of these questions, throw it out.
Sniff - Open the jar and sniff. Can you smell the herb or spice? If there is no odor, then it is probably devoid of essential oils and should be discarded. If the scent is faint, but noticeable, it may still be good.
Taste - Finally, taste a small portion of the contents. If the distinctive flavor is still there, keep it. But if it tastes no better than cardboard or grass clippings, throw it out.
Finally, do not shake spices out of the bottle directly into something you're cooking — that's the quickest way possible to introduce steam into your spices and you'll end up with a large, hard clump the next time you use them.