How to dry herbs: Methods and tips

Having fresh herbs at the ready is the dream of every home grower. The benefits of growing your own herbs are many: fresh herbs taste better, contain higher levels of nutrients, and are guaranteed to be organic. But what happens when herbs can’t be used immediately, or when an overabundance of herbs needs to be harvested, stat?

Much thought has gone into this dilemma (1), but most agree that the easiest solution is to process fresh herbs into dried herbs. These dried versions of herbs will still be fresher than any available on grocery store shelves and will extend a herb’s life long beyond the growing season.

While many people want to harvest herbs at home for cooking and eating, most people have never considered drying herbs. The task may sound daunting, but the reality is that it couldn’t be easier. There are numerous ways that herbs can be dried quickly and easily, without any specialized equipment. After becoming familiarized with a few of the techniques for drying herbs, the best path is to choose a drying method and experiment with it. The following is a complete guide on how to dry herbs.

Why dry herbs in the first place?

Preserve flavor

Let’s face it, herbs are grown for their flavor, and the primary objective of preserving them for future use is to maximize that flavor (2). Most Herbs generally have the best flavor when harvested just before blooming. Excellent results can, however, be achieved year-round. For harvesting an entire plant at season’s end, cut it to the ground. For midseason harvests or harvesting from a perennial herb, never cut more than one-third of a plant. Only preserve the best stems and leaves, toss out any parts that are dead or wilted.

Using the heat of the sun to accelerate drying times may be tempting, but direct sunlight can be detrimental to the color and flavor of herbs. However, done one carefully in shade on warm days with low humidity (less than 60%), solar drying may be preferable to oven-drying (3). Just be sure not to leave drying herbs outdoors overnight, as dew can ruin them.

Preparation

Tender-leafed herbs

Herbs with high levels of moisture such as basil, oregano, mints, and tarragon must be dried quickly or they risk molding. These do well inside a paper bag or dried with leaves removed from stems.

Harvesting and preparing herbs for drying

Before drying herbs, they should be prepared appropriately. To harvest herbs, start in the morning as soon as the dew has dried (for outdoor plants), and use scissors or pruning shears to cut the stems above the soil line. For herbs grown outdoors, rinsing may be necessary to remove any dirt or insects from the leaves. For indoor-grown herbs, rinsing is rarely necessary.

For air-drying, it is ideal to make small bundles of herbs, which can be easily done by wrapping the base of the stems with natural twine and tying the ends securely. The bundles should be small enough that there is air circulation through the leaves– packing too tightly can lead to incomplete drying, which encourages mold growth. Herbs are dry when the leaves easily crumble.

close up of dried peppermint herb

Dried peppermint. Photo: Marco Verch

Comparing methods

The best way to dry herbs will depend largely on the logistics and environmental conditions at hand. For someone living in a small apartment without a lot of space, drying herbs in the oven or microwave is an ideal method. Microwave drying is particularly helpful when pressed for time. For anyone working with a larger volume of herbs and limited suitable space, a food dehydrator may be the answer. On the other hand, those with ample indoor space or access to a protected outdoor area, air drying out of direct sunlight can work beautifully.

Air drying is arguably the easiest way to dry herbs, but it takes the longest. Microwaving is the fastest, but requires paying close attention and may not yield the best results. Oven drying is effective but also requires close attention and can ruin flavor if the heat is too high. A dehydrator offers the benefit of speed and control over variables. Different herbs will respond to techniques in different ways, so experimenting is always a good idea.

Hang and air drying herbs

Air drying herbs on a tray or hanging them is a fantastic way to dry herbs without special equipment if there is an appropriate space to do so. The best herb drying spot will be out of direct sunlight, clean, dry, and free of dust, smoke, or steam. Despite photogenic images of herb bundles hanging in kitchen windows, basements and closets are much better locations for drying herbs.

  1. Harvest and rinse herbs only if necessary. Dry thoroughly if rinsed.  
  2. Pluck leaves from lower two inches of stems.
  3. Facing all stems in the same direction, bundle a small handful together tightly using twine or rubber bands. Alternately, place leaves or stems in a single layer onto drying trays or a paper bag on its side.
  4. Hang herbs, leaves-down, securely attached to a rod, line, or hook to keep them off the ground. If you are tray drying, set up your trays where there is adequate circulation.
  5. Check on the herbs every few days, but know that it can take up to a few weeks for herbs to fully dry.

Drying herbs in the oven

Oven-drying herbs is an effective way to dry larger batches than is possible in the microwave, but it can be a little aggressive and works best with hardy herbs like sage, thyme, and rosemary. Because the temperature of ovens varies wildly, it is best to use a thermometer and be prepared to do a bit of troubleshooting to find the setting that works best.

  1. Remove the stems from large leaves and lay the leaves in a single layer on an oven rack covered a layer of parchment paper. For herbs with fine leaves, you may prefer to leave them on the stems.
  2. Place the rack in the oven at the lowest heat setting possible. Most ovens do not go below 100 degrees, which is the highest temperature herbs should be in for. An oven thermometer can help to find the sweet spot, temperature-wise.
  3. Leave the door cracked open to let excess moisture vent out and to keep the temperature lower.
  4. After 30 minutes, turn your herbs over to the other side. Check to see how dry they are, and if needed, return to the oven for another 15 minutes. Repeat again if necessary.
  5. Once the herbs have spent an hour in the oven, turn it off and let the herbs cool.
  6. Alternately, gas ovens with a pilot light may generate sufficient ambient heat to dry tender herbs left on trays overnight.

hang dried thyme

Bunch of thyme. Photo: Marco Verch

Drying herbs in a microwave

Microwaves work by heating the water molecules in food, which makes it a fantastic device for drying herbs. This method will dry herbs faster than any other, while still maintaining color and flavor. This method is best for drying small batches of delicate herbs, like dill or cilantro, but will work for all herbs.

  1. If herbs have been rinsed, make sure there is no water whatsoever on them before you begin this process.
  2. Remove the leaves from the stems, when applicable.
  3. Cover the surface of a microwave-safe plate with a layer of paper towel. Spread the leaves out in a single layer and cover them with another paper towel.
  4. Set the microwave to high and microwave for 1 minute. Stay close by and, make sure you don’t smell any burning. If you do, stop the microwave immediately.
  5. Continue to dry herbs for 30-seconds at a time, until they are crisp and crumble easily. Some herbs with very high moisture content can take up to ten minutes to fully dry.

Drying herbs in a dehydrator

A food dehydrator works by extracting the moisture from foods with a heating element and fan. Typically, there are multiple shelves, settings, and a timer– making this one of the most efficient ways to dry herbs. Multiple types of herbs can be dried simultaneously on different shelves, and with the timer, it is possible to set it up and walk away.

Herbs are preserved best under 100 degrees because the essential oils that give them their flavor are volatile and can degrade under high levels of heat.

A dehydrator takes the guesswork out of the drying process by ensuring a consistent low heat with constant air circulation. Very dense things like roots must scrubbed, peeled, and sliced thin and may take up to 10 hours to dry. Most herbs, however, will be fully dry in 1 to 4 hours.

  1. Prepare herbs as needed, removing leaves from stems if necessary. Lay out leaves and herbs in a single layer onto multiple dehydrator trays.
  2. Keep track of which herbs are on which trays– they can be difficult to distinguish once dried.
  3. For drying seed heads or blossoms, line trays with cheesecloth to ensure that petals and seeds stay put.
  4. Place the trays into the dehydrator and adjust the heat and timer setting.
  5. Check on the trays after 90 minutes to gauge dryness. Make notes to track how long each herb takes to dry for future reference.

Storing dried herbs

Once dried, preserving the flavor of herbs is a matter of storing them in airtight containers out of direct sunlight. Storing leaves whole will preserve more flavor than grinding or powdering herbs, but they will take up more space. For best results, label and date clearly and use within a year. Most herbs will still be perfectly usable after a year but will have lost some potency over time.

Conclusion

Regardless of the method used, dried herbs are a wonderful way of extending homegrown herb use well beyond the growing season. Beyond the pleasure of producing herbs at home for less than you would spend at the grocery store, the flavor homegrown dried herbs provide far surpasses anything commercially available. Truly, a gift that keeps on giving.

Sources:

  1. https://extension.colostate.edu/topic-areas/nutrition-food-safety-health/herbs-preserving-and-using-9-335/
  2. https://www.smithsonianmag.com/arts-culture/saving-the-flavor-of-fresh-herbs-44057191/
  3. https://scialert.net/fulltextmobile/?doi=ajcs.2018.151.159

Feature Photo: Christopher Paquette