Fresh thyme has a brighter, more delicate flavor that is best added towards the end of cooking, while dried thyme has a more concentrated, earthy flavor that holds up well during long simmering times in stews.
The primary difference between fresh and dried thyme lies in their flavor intensity and how they interact with heat. Fresh thyme contains volatile oils that contribute to its bright, herbaceous aroma and flavor. These oils are delicate and can dissipate with prolonged cooking. Therefore, fresh thyme is best added towards the end of the stewing process to preserve its flavor.
Dried thyme, on the other hand, has already undergone a drying process, which concentrates its flavor and reduces the volatile oil content. This results in a more robust, earthy flavor that can withstand long cooking times without losing its potency. Dried thyme is typically added at the beginning of the stewing process, allowing its flavor to fully infuse into the dish.
In terms of quantity, a general rule of thumb is to use about one-third the amount of dried thyme as you would fresh thyme. For example, if a recipe calls for 1 tablespoon of fresh thyme, you would use approximately 1 teaspoon of dried thyme. This is because the drying process concentrates the flavor.
When using fresh thyme, consider adding the whole sprigs to the stew and removing them before serving. This allows the flavor to infuse without the leaves becoming too dispersed throughout the dish. For dried thyme, crush it slightly between your fingers before adding it to the stew to release its aroma.