If you're not going to use them right away, you can store unwashed herbs for up to 1 week. Place bunches of herbs with their stems in a vase of water in the refrigerator. (Be sure to keep the leaves out of the water.)
Pack loose leaves in perforated plastic bags in the refrigerator. Place a dry paper towel at the bottom of the bag to absorb excess moisture, which can promote decay.
Once you're ready to use your herbs, you'll want to clean them. Place them in a sink or large bowl of cool water that has salt added to it. (The salt will drive away insects without damaging the herbs.) Gently swish the herbs in the water, remove them and dry them in a salad spinner or place them on paper towels and pat them dry.
Remove leaves from herb stems, like thyme, by holding the top of the stem and running your fingers down the stem in the opposite direction of leaf growth. Herbs with larger leaves, like basil, should be snipped from the stems.
To use in recipes, chop herbs by placing them in a small bowl and using the tips of kitchen scissors to snip them. For longer storage, consider freezing or drying your herbs once you've cleaned them.
Freezing and Drying Herbs
Herbs can be frozen for up to 4 months. Freeze whole herbs on a tray for about 3 hours, then crumble them, put them in freezer containers or heavy-duty resealable bags and return them to the freezer. This way, you can remove a desired amount a spoonful at a time.
You can also freeze chopped fresh herbs in freezer containers or bags; measure the desired amount as needed.
Another way to freeze herbs is to make them into herb ice cubes. Put chopped herbs into an ice cube tray and cover with water or stock. Once frozen, the cubes can be stored in plastic containers. They're particularly good for adding directly to sauces and soups. Use herb cubes without thawing.
If you prefer, you can dry your herbs instead. Tie them together in little bunches by the stems, then hang them upside-down in a well-ventilated place. Or spread them loosely on a sheet of paper and let them air-dry.
You can also use your microwave to dry them. Cover the turntable or a plate with a piece of paper towel. Arrange small sprigs of herbs in a single layer and microwave on low power for about 3 minutes or until dry enough to crumble, turning the leaves half-way through.
Stored in a tightly closed container in a cool dark place, dried whole herbs can be kept 1 year while dried crushed or ground herbs can be kept for 6 months.
To substitute dried herbs when fresh herbs are called for in a recipe, use 1/4 teaspoon ground or 1 teaspoon crumbled dried leaves for every tablespoon of fresh herb finely chopped.