How To Substitute Dried Herbs For Fresh
We've all been there: You come home with groceries ready to make something fresh for dinner that evening. You bypassed the fresh herbs in the store, remembering you had bought some a few days earlier. As you're unpacking your haul, you check your produce bin and find your fresh basil has turned into a wet mushy substance better suited for composting than cooking. If you have fresh oregano or mint on hand, you can try using them as a substitute, but if you have some dried basil tucked away in your spice drawer or rack, don't be daunted. Just keep in mind the rule of thumb that says to use a third of the amount of dried herbs than would have with fresh. So, if you planned to use a tablespoon of fresh herbs, this 3-to-1 ratio means you'll only need 1 teaspoon of dried.
While the fresh kind may seem to have more flavor than dried, most leafy herbs will contain 75 to 90% water. Because the moisture has been removed from dried herbs, they will have a more concentrated flavor. Remember that dried herbs and spices should be replaced every two to three years. If you've kept yours longer than that, you may want to use more. You can also try crushing the dried herbs to release more of the aroma and flavor.
A few exceptions to the rule
The same rule of thumb doesn't apply to all spices. For garlic, you'll need half a teaspoon of powder per fresh clove. For ginger and turmeric, use a quarter teaspoon of ground for each teaspoon of fresh. You'll need 1 teaspoon of onion powder for each medium fresh onion. The flavor of ground herbs is even more concentrated, so use half of the amount of dried leafy herbs. For each tablespoon of fresh, use half a teaspoon of the ground alternative.
In addition to changing the amount of the herb you're using when switching dried herbs for fresh, you also need to switch up the timing of when you use them. Dried herbs should be used at the beginning of the cooking process and fresh herbs toward the end. Heat can turn fresh herbs bitter if applied for too long. In fact, it may be better to use dried herbs for something that will be on the stove for a long period of time.
Of course, the best course of action is preventing the herbs from turning to mush in the first place. If you don't plan to use everything you've purchased, try drying or freezing them. One way to preserve fresh herbs is to dry them in the microwave, or you can try Alton Brown's method using a box fan and air filters.