What's the difference between spices and herbs? Generally, spices come from flowers, seeds, fruit, roots, or bark, while herbs come from leaves and stems. As a practical matter, the two terms are often used interchangeably, since they both serve the same purpose: to make food taste better. There are a few rules to follow in order to get the best flavor out of your herbs and spices. When possible, buy spices in their whole form. Ground spices lose much of their flavor within a few months, while whole ones keep well for a year or more. Get a coffee grinder and use it exclusively for grinding up whole spices, unless you want very strange tasting coffee.. Store your spices in a cool, dark place. Light, air, and humidity are the enemies of spices. Refrigerator storage has one big drawback: whenever you open the cold container, moisture immediately condenses on the spice. One solution is to divide your spices into individual doses of a teaspoon or so and store them in the refrigerator. Here's a tip for fresh herbs: put a teaspoonful in each compartment of an ice cube tray, fill the tray with water, cover with plastic wrap, and freeze. Once the spice cubes are frozen, transfer them to a plastic bag for later use.