How to Dry Mint: Dehydrator, Air, Oven and Microwave

Mint needs to dry quickly. Four university extension guides put the mints among the tender, high-moisture herbs that will mold if they are not dried fast,¹²³⁴ and the University of Wisconsin’s guidance says a dehydrator is the best tool for them.³ Air-drying works too, if you use small bunches or single leaves and the air is dry. Dried mint goes into cooking and into tea; NCCIH notes that peppermint tea is made from the leaves.⁵ The settings below come from university extension guides; where they disagree, the disagreement is shown rather than averaged.

At a glance

Method	Settings from named sources	Time	Notes
Dehydrator	95–115°F, up to 125°F where humid¹; Penn State says 95–110°F⁶	1–4 hours¹	Best for high-moisture herbs like mint³
Air-drying, bagged bunches	Small bunches inside a paper bag with vent holes, where air circulates²	Usually 5–10 days²	Works best when humidity is low³
Air-drying, single leaves	Leaves on paper towels on a tray²	Until crisp	Suits mint especially¹²
Oven	Lowest setting, not above 180°F, door open⁶	3–4 hours⁶	Or overnight with only the oven light on¹
Microwave	On high, from 30 seconds to 3 minutes depending on the source (table below)	Minutes	Small batches only; paper towels can catch fire⁶
Sun	Not recommended⁶¹²		Costs color and flavor¹

Before you start

The extension guides agree on timing: the best point to harvest most herbs for drying is just before the flowers first open,¹² picked in the early morning once the dew has evaporated.² Oregon State adds that cut herbs should not lie in the sun or sit unattended after harvest.²

Rinse the stems in cool water and shake off the excess,⁶¹ then remove all visible water with towels or paper towels.³ A widely repeated claim says rinsing rids herbs of pathogens; the extension guides present it as cleaning and make no such claim.

Dehydrator

This is the method to reach for with mint. The Wisconsin guide says a dehydrator is best for high-moisture herbs.³ NCHFP’s instructions are to preheat with the thermostat at 95–115°F, going as high as 125°F where humidity is high, and to expect 1–4 hours, checking periodically.¹ Penn State’s range tops out lower, at 110°F.⁶ Strip the leaves or lay whole sprigs in a single layer (common practice), and start checking at the one-hour mark.

Air-drying

Mint can be air-dried, but it is less forgiving than sturdy herbs like rosemary. The Wisconsin guidance is that moist herbs air-dry most successfully when relative humidity is low; tie them in smaller bunches, check the bunches for mold now and then, and throw out any that show it.³

Bagged bunches. Oregon State’s method for tender herbs is to tie small bunches (large amounts will mold), hang them inside a paper bag with vent holes cut in the top and sides, close the top with a rubber band, and put the bag where air moves through it. It usually takes 5–10 days.² Penn State says to keep drying herbs away from the sink, stove and dishwasher, where the air is moist.⁶ NCHFP says drying indoors usually gives better color and flavor than drying outdoors.¹

Single leaves. NCHFP calls drying the leaves separately “especially nice” for mint,¹ and Oregon State says spreading leaves on paper towels on a tray works well for mint.² A window screen or a frame covered in fine mesh, propped on blocks so air reaches underneath, does the same job; keep to a single layer in a warm, dry room.³

Oven

An oven works only if it can run cool. Penn State’s method is the lowest temperature, not above 180°F, for 3 to 4 hours with the door open,⁶ and the Wisconsin guide gives the same figures, with the herbs in a single layer and stirred now and then.³ Oregon State warns that drying herbs at too high a temperature can cause flavor loss.² Short oven sessions of 15 to 30 minutes at 180 to 200°F are often suggested for mint; none of the extension guides we checked recommends one.

The cool-oven method suits mint leaves well. Lay leaves on a paper towel so they don’t touch, cover with another towel and another layer of leaves, and repeat for up to five layers. Leave them overnight in an oven warmed only by the light of an electric oven or the pilot light of a gas one.¹⁴

Microwave

The microwave is fast and suits small amounts only.¹ The guides do not agree on the timing:

Source	Amount	Time on high	Method
Penn State⁶	Per cup	2–3 minutes	Start with 1 minute, mix every 30 seconds, keep checking
University of Tennessee⁴	Per cup	2–3 minutes	Start with 1 minute, mix every 30 seconds
Oregon State²	1 cup (never more than 1–2 cups)	1–2 minutes	Stir every 30 seconds after the first minute until almost dry, then finish at room temperature
University of Wisconsin³	4 or 5 branches between paper towels	2–3 minutes	Another 30 seconds if not brittle
America’s Test Kitchen⁷	Not stated, on a paper towel	30–40 seconds	Crumble and store

As a starting point (Method), begin with a minute or less, then check every 30 seconds until the leaves crumble. A common claim says the microwave keeps mint’s appearance better than other methods; we found no source for that, and the Wisconsin guide rates microwaved herbs as poor in quality.³

Two safety points apply whatever the timing. Penn State warns that if the load is too small, the paper towels can catch fire,⁶ and Oregon State says not to use paper towels made from recycled paper, which can contain metal scraps that arc.² The Wisconsin guidance calls the microwave a last resort that cooks the herbs and gives very poor quality, and notes that the heat drives off some of the oils along with the water, so microwaved herbs may taste less intense than herbs dried other ways.³

Where the guides disagree

Question	What named sources say
Dehydrator temperature	95–115°F, up to 125°F where humidity is high (NCHFP, Tennessee, Oregon State)¹²⁴; 95–110°F (Penn State)⁶
Air-drying time	Generally 2–4 weeks for sturdy herbs hung in bundles (Wisconsin)³; usually 5–10 days for tender herbs hung in small bunches inside bags (Oregon State)²
Microwave time	From 30–40 seconds (America’s Test Kitchen) to 2–3 minutes per cup (Penn State, Tennessee); see the table above
Oven	Lowest setting up to 180°F with the door open for 3–4 hours (Penn State, Wisconsin)⁶³; or no heat but the oven light or pilot light, overnight (NCHFP, Tennessee)¹⁴

None of these was tested side by side on the same herb, so we have not picked a winner. Where a range is given, starting low and checking often is the cautious reading (Method).

What drying does to mint

Drying changes mint’s character, and the method matters. A 2003 study dried spearmint three ways: in an oven at 45°C (113°F), in air at room temperature, and by freeze-drying.⁸ Carvone, limonene and 1,8-cineole, in that order, were the main aroma compounds in every sample. The oven at 45°C and room-temperature air gave the best results, while freeze-drying caused substantial losses of oxygenated terpenes and sesquiterpenes.⁸ In sensory terms, drying reduced the herbaceous and floral notes and increased the minty odor.⁸ The study covered spearmint only; we found no comparable study for peppermint.

America’s Test Kitchen puts mint among the herbs better used fresh, because delicate herbs are much weaker in flavor once dried.⁷

How to tell it’s done

Herbs are dry when the leaves are crisp and crumble easily between the fingers⁶ and the stems break when bent.¹ Oregon State adds that the leaves should fall from the stems.² Strip the leaves and discard the stems.³

Check your work after packing. The Wisconsin guidance is to watch the filled containers for a couple of days; if you see any moisture, take the herbs out and dry them longer.³

Air-dried herbs can carry insects. The University of Tennessee says air-dried herbs and seeds need treating to kill insects and their eggs, either by heating at 160°F for 30 minutes or by freezing at 0°F or lower for at least 48 hours, and it recommends freezing for better flavor.⁴

Storing dried mint

Keep the leaves whole and crumble them as you cook; Penn State says storing herbs whole is preferred.⁹ Use airtight containers in a cool, dry, dark place,¹ away from the stove and sink.⁶ Oregon State adds that dried herbs can also go into airtight containers in the freezer.²

How long dried mint keeps depends on whom you ask, and none of these figures was measured on mint:

Source	Scope	Figure
Penn State⁶	Most home-dried herbs	Keep well for up to a year
Oregon State²	Home-dried herbs	Up to one year; for best flavor, use within six months to a year
University of Wisconsin³	Home-dried herbs	Keep for years, but use within a year for best flavor
America’s Test Kitchen⁷	Herbs dried in the microwave by its method	Up to 3 months, airtight
McCormick¹⁰	Leafy dried herbs, a spice company’s own guidance	1–3 years

We have not averaged these. McCormick defines shelf life as how long spices stay most aromatic,¹⁰ which is the right way to read every figure here: a quality window, not a safety date. The practical test is smell. Crush a pinch, and if the aroma is faint, the mint has faded.

Herbs in oil are a separate food-safety question. A 2011 review of home-prepared vegetables and herbs stored in oil advises refrigerating them and using them within four days or discarding them, and calls freezing the safest option.¹¹

Not yet measured

How home drying methods change peppermint’s aroma compounds.
How long home-dried mint keeps, measured on mint rather than herbs in general.
Microwave times by oven wattage for mint.

Herbs (drying), National Center for Home Food Preservation. nchfp.uga.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸
Drying herbs (SP 50-921), Oregon State University Extension Service. extension.oregonstate.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹
Drying Herbs, Wisconsin Master Gardener Program, University of Wisconsin-Madison. mastergardener.extension.wisc.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷
Drying Herbs, University of Tennessee Extension. lawrence.tennessee.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Peppermint Oil, National Center for Complementary and Integrative Health. nccih.nih.gov · Regulator ↩
Let’s Preserve: Drying Herbs, Penn State Extension. extension.psu.edu · Reference work ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶
When You Should Actually Use Dried Herbs, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩² ↩³
Díaz-Maroto et al., Journal of Agricultural and Food Chemistry, 2003 (abstract). pherobase.com · Peer-reviewed ↩ ↩² ↩³
Preserving Herbs by Drying, Penn State Extension. extension.psu.edu · Reference work ↩
How Long Do Spices Last?, McCormick. mccormick.com · Merchant ↩ ↩²
Nummer et al., Food Protection Trends, 2011. foodprotection.org · Peer-reviewed ↩

How to Dry Mint Without Losing It to Mold