When it comes to preserving our own food, growing and drying herbs is one of the best jumping-off points. Many herbs are incredibly easy to grow, and most contain so little moisture that the preservation job is done soon after they’re harvested. Drying herbs and spices also makes good economic sense considering the cost of high-quality seasonings and teas. And when we grow our own, we know with certainty we are getting herbs that are both fresh and organic. Lastly, when you grow your own herbs, you can grow the particular varieties that appeal to you and experiment with creating your own custom herb blends.
Herb and Spice Drying Basics
According to The Deluxe Food Lover’s Companion by Sharon Tyler Herbst and Ron Herbst, culinary herbs are leaves, while spices are obtained from the bark, berries, buds (and even flower stigmas), fruit, roots and seeds of plants. Spices are almost always used in dried form, whereas herbs can be used fresh or dried. Here are a few examples: bark (cinnamon); berries (peppercorns); buds (cloves, lavender); fruit (chili peppers, vanilla beans); leaf (cilantro, parsley); roots (garlic, horseradish); seeds (coriander, juniper); and stigma (saffron).
To preserve your homegrown herbs, harvest them in midmorning before newly developed essential oils have been burned off by the sun, but after the dew has dried. Remove old, dead, diseased or wilted leaves. Washing fresh herbs usually isn’t necessary if they are grown organically.
When you harvest seed spices, the seed heads should begin to turn brown and harden, but not yet be ready to shatter. To harvest herbs for their flowers—such as chamomile flowers or thyme spikes—snip flower buds off the plants close to the first day the buds open.
Fully dried herbs and spices are safe from bacteria, mold and yeast, and will remain potent for at least six to 12 months. To remove moisture, all you need is air circulation. Some warmth can also help. The six methods detailed here fit the bill.
To air-dry herbs on stems, tie stems in bundles and hang the herbs upside down in a warm, dry place (avoid the kitchen, a source of steam and cooking vapors). Use twist-ties or thin-gauge wire so you can easily tighten the bundles as the drying stems shrink. Wrap bundles with muslin, a mesh produce bag or a paper bag with several holes, and tie it at the neck. If you’re drying individual leaves, flowers or sprigs, make a drying screen from an old window screen or hardware cloth or mesh stapled to a wooden frame. Lay cheesecloth over the screen, and place herbs on the cloth. Once herbs are fully dry, which can take anywhere from a few hours to a few days, prepare them for storage as outlined in “Storing Herbs & Spices” on the last page.
This method is ideal for warm, dry weather around 100 degrees and 60 percent humidity or less. In these conditions, you can use the sun’s heat to dry herbs. Don’t expose herbs to too much direct sunlight as this could cause them to bleach. Solar drying can be as low-tech as placing drying screens outside until your herbs are brittle (bring them in at night). You can also dry herbs under the windshield or rear window of your car on a hot day. Or build your own solar food dehydrator with stackable drying screens, a glass top to trap radiation, an absorber plate to transmit heat and a vent for air circulation. Find building plans online.
Another supersimple method of drying herbs basically amounts to neglect. Just stick them in the fridge and forget about them for a few days. This handy tip was discovered by the late herb authority Madalene Hill and her daughter Gwen Barclay. By accident, they discovered that herbs left alone (out of packaging) in a cold, dry refrigerator dried beautifully crisp and also retained their color, flavor and fragrance. They even liked this method for parsley and chives, which don’t have the best reputation for keeping great flavor in dried form. The challenge is finding enough room to let herbs sit uncovered for a few days. If your fridge has available space, by all means, give it a try.
Dehydrating With a Machine
Commercial food dehydrators range in price from $30 to $400, but for most of us, a machine that costs $100 to $200 is the best choice. Quality dehydrators have handy features such as timers and adjustable temperature control. Stored in a convenient spot, you’ll use your dehydrator often and recoup its cost in a season or two of grocery savings.
Most dehydrators have a temperature-control mechanism—ideally one you can adjust—and a fan to circulate air. Round models with multiple stacking trays are the most energy- efficient. Box-type models that allow you to remove some of the trays can be handy for drying large items and can serve other purposes such as proofing bread dough or culturing yogurt. Follow your machine’s instructions.
Although drying herbs and spices in an oven sounds easy (most of us already have one and know how to use it), this is actually the most labor-intensive and least energy-efficient method. Herbs need to be dried at about 100 degrees, but most ovens don’t go that low. They also need air circulation, and some ovens don’t have vents. If you wish to dry your herbs this way, it’s best to get an oven thermometer and experiment. Try turning the oven on warm or its lowest setting for a while, then turning it off (while leaving the light on). You can also try propping the door open slightly with a wooden spoon. Note how long it takes for the temperature to drop to 100 degrees and how long it stays at that temperature.
Herbs are far easier than fruits and vegetables to oven-dry because they dry more quickly and are more forgiving. If you plan to learn how to use your oven for food dehydration, definitely start with herbs. Layer them on a cheesecloth over a wire cooling rack to allow for air circulation all around, and place the rack in the middle of the oven when the temperature is about 100 degrees.
The microwave can successfully dry herbs, but note that food-drying experts do not recommend it for drying foods that have more moisture. It’s not as easy as air-drying or using an electric dehydrator.
To dry herbs in a microwave, strip leaves off of the stems and place the leaves between layers of paper towels. Begin on high power for 1 minute, allow a 30-second rest, and then alternate between 30 seconds on high power and 30 seconds of rest. Most herbs should dry fully in 10 minutes or less.
Choosing Herbs and Spices for Drying
There are more herbs and spices on this planet than we could possibly list here—the following are commonly grown in home gardens in North America and are good candidates for drying. Some herbs, although they can be dried, retain their flavor better if frozen. These include basil, borage, chives, cilantro, lemongrass, mint and parsley. To freeze herbs, chop them and put them in ice cube trays, then cover with water and freeze. Alternatively, mix chopped herbs with a bit of olive oil and freeze. Use frozen herbs in dishes where they will melt easily, such as soups, sauces and stir-fries.
Leaves: Bay, celery, chervil, dill, geranium, lemon balm, lemon verbena, lovage, marjoram, oregano, rosemary, sage, summer savory, tarragon, thyme
Seeds: Anise, caraway, celery, chervil, coriander, cumin, dill, fennel, mustard
Flowers: Bee balm, chamomile, chive, dill, geranium, lavender, linden, marigold, nasturtium, rose, thyme, yarrow
Fruits: Hot peppers
Roots: Garlic, ginger, horseradish (Note that these take much longer to dry than seed spices and leaf herbs. It is useful to cut them into thin slices first.)
Storing Dried Herbs and Spices
Herbs and spices have finished drying when the leaves crumble easily wand no longer feel leathery—but don’t crumble them. Whole leaves and seeds retain their oils better in storage. Store dried herbs in airtight jars out of direct light and away from heat. Label jars immediately with the date and contents, including the specific variety so you can pinpoint favorites over time. After a few days, check new jars for droplets of moisture or mold. Throw out anything moldy, and redry anything that creates moisture in the jar.
Although whole herbs and spices hold up better, having some premixed ground blends—such as those for Italian, Mexican or barbecue dishes—can be a big time-saver (to make an Italian herb blend, mix 2-1/2 tablespoons each dried oregano and basil and 1 generous tablespoon dried marjoram). Grind ingredients with a mortar and pestle. When using dried herbs in recipes that call for fresh, keep in mind that oils in dried herbs are more concentrated. Use about half the amount of dried herbs, and about a quarter as much if the herb is finely ground.
Tea blends are also useful, such as a combination of peppermint and fennel to calm an upset stomach. To use herbs in teas, pour boiling water over a teaspoon to a tablespoon (to taste) of the dried herb and steep for 5 to 10 minutes. Strain and enjoy.