The advantage of drying herbs is that dried herbs are stronger than the fresh ones. Herbs that are fresh still contain all the water in them. The herbs that are dried have more concentrated essential oil. You will find you do not need to use as much of the dried herbs to get the same flavors.
There is a myth that herbs can be oven dried or heated to force dry them. This is not the proper way to dry herbs. The heat can actually release the essential oils which give the herbs their wonderful aroma and flavor. The dehydrator is a different story, used by people that only eat raw, the dehydrator dries your herbs as natural as possible.
The important thing to remember is to make sure the herbs are kept in a warm, dry, and ventilated area for the herbs to dry which is exactly what a dehydrator does for you.
