How to Use a Food Dehydrator to Dry Herbs

Rosemary: fresh and dried
Rosemary: fresh and dried. Getty Images/Donald Erickson
  • 01 of 06

    Using Your Home Food Dehydrator

    Excalibur Food Dehydrator
    Excalibur Food Dehydrator. © Excalibur, used with permission.

    If you live in a climate of eternal sunshine, preserving food by drying is virtually effortless. But if you live elsewhere, or want greater convenience, you should consider home food dehydrators

    Home food dehydrators fall into two categories—those with stackable trays and those constructed of a rigid box with removable shelves. Size is a factor as most fit on a countertop, but larger models are free-standing and require more space. Some models have base-mounted fans that move hot air vertically....MORE Others have a rear-mounted fan for moving air horizontally. Others use convection drying, with no fan at all.

    Stackable Dehydrator Units

    While these models may stack up to 30 inches tall, they have a small footprint and consume little counter space. They also provide the least expensive way to get started with food dehydrating. However, they all share one big limitation—uneven heat distribution in the stack means that the trays closest to the heat element and fan dry much faster than those at the top of the stack. Diligent tray rotation is critical, especially if very fleshy foods are being dried. And while perfectly suitable for drying herbs, fruits, vegetables, fruit leathers, and jerky, these machines cannot readily be adapted for any of the other uses the box-and-shelf models can claim.

    Box-and-Shelf Dehydrator Units

    Some of box-and-shelf dehydrator units position the heat source and fan at the back of the shelves instead of beneath them. Hot air blowing across the shelves eliminates the bothersome need for tray rotation. Some large models are big enough for other uses with some shelves removed, such as leavening bread, culturing yogurt, or drying bulky items.

    Others, instead of using a fan, rely on convection drying. Heat is generated by a heating element mounted at the base of the box and rises through the trays. A benefit of convection drying is that it eliminates the possibility of contaminating foods with dirt that fans can suck into a dehydrator. However, placing the fan-powered dehydrator in a clean space remedies that potential problem.

    Convection heating allows silent operation and less use of electricity. It is good for drying herbs, but it takes twice as long as fan models to dry bulky, moisture-laden foods like tomatoes and peaches. The longer the drying time (especially during periods of high humidity), the more the dried product's flavor and shelf life are reduced.

    Continue to 2 of 6 below.
  • 02 of 06

    Remove Long Stems and Damaged Leaves

    Mint leaves being prepared for drying
    Mint. ©2008, A. Jeanroy, Licensed to About.com

    To dry herbs, begin by removing any long stems and damaged or bruised leaves. But you can leave a bit of stem near the leaves for mint, basil, or any other herbs you are drying, and then remove the dried leaves before storing. This cuts down on the time it takes to get the herbs into the dehydrator when you are busy trying to harvest the entire fall garden. It also prevents bruising or damaging the leaves, which will reduce their quality when dried. 

    Continue to 3 of 6 below.
  • 03 of 06

    Place in a Single Layer on the Dehydrator Tray

    Dehydrator tray of mint leaves
    Fresh Mint Leaves. ©2008, A. Jeanroy, Licensed to About.com

    Place leaves in a single layer on the dehydrator tray. The leaves will dry more evenly. You may need to cover the dehydrator tray with a fine screen to prevent herbs from falling down into the bottom.

    Continue to 4 of 6 below.
  • 04 of 06

    Remove Tray Above for Good Airflow

    Remove tray for better airflow
    Remove Tray Above Larger Leaves. ©2008, A. Jeanroy, Licensed to About.com

    Remove any trays that are not necessary to allow enough space for larger leaves. It is important that all leaves receive plenty of air circulation.

    Continue to 5 of 6 below.
  • 05 of 06

    Dry on the Lowest Setting Possible

    Dry on lowest setting
    Dry On Lowest Setting. ©2008, A. Jeanroy, Licensed to About.com

    For the best flavor, dry herbs on the lowest setting possible. If your dehydrator does not have a thermostat option, use the shortest period of time possible and check on them often. A suggested temperature is 95 F to 115 F, but if you have high humidity, you may need to use 125 F. Typical drying time is one to four hours.

    Continue to 6 of 6 below.
  • 06 of 06

    Storage

    Crumble dried herbs
    Crumble dried herbs. ©2008, A.Jeanroy, Licensed to About.com

    It is always best to leave herbs in their whole form when storing them, as this best preserves their aroma and flavor. Then you can crush them immediately before using them. It's more convenient to crumple herbs for blending and storing if you are going to use them for tea.

    Store your dried herbs in an airtight container and keep it in a cool, dark, dry location. While you may want to display them, any light or warmth will lead to faster deterioration. You should be able to enjoy the best...MORE flavor if you use them within six months to one year.