Drying Fresh Herbs

Drying is a process that removes most of the water in an herb, which when fresh may be more than 90% water. The basic dilemma is that many aroma chemicals are more volatile than water, so any process that evaporates most of the water will also evaporate most of the flavor. This is why many dried herbs don’t taste anything like the fresh version, and instead have a generic dried-leaf, hay aroma. There are a few exceptions to this rule, mainly Mediterranean herbs in the mint family that are native to hot, arid areas and have aromatics that persist in drying conditions (oregano, thyme, rosemary, as well as bay laurel from the laurel family). Though sun-drying sounds appealing, its high temperatures and strong dose of visible and ultraviolet light mean that it generally removes and alters flavor. Air-drying over the course of a few days in the shade is much preferable. Herbs can be dried in just a few hours in a low oven or a dehydrator, but the higher temperature usually causes greater flavor losses than air-drying. Some commercial herbs are freeze-dried, which often preserves more of the original flavor.