Walk past a supermarket herb rack in February and you will see the problem: pale, dusty leaves that smell of very little. The herbs you dried yourself in July, from plants you actually grew or bought fresh, keep far more of their character — provided you dry them properly. Get it wrong and you end up with hay. Get it right and a pinch of your own thyme or oregano will still taste of summer when the garden is bare. All three common methods work; they simply suit different herbs and different kitchens.

Pick at the right moment

Timing matters more than equipment. Cut herbs mid-morning, once the dew has dried but before the day's heat has had a chance to drive off the aromatic oils that give them their flavour. Choose healthy stems that have not started to flower — once a herb bolts, the leaves turn bitter.

Handle them gently. Bruising releases oils into the air rather than into your jar. If the plants are dusty, or you picked them from a hedge beside a road, rinse them in cool water, shake well, then lay them on a tea towel and pat dry. Wet herbs are the main cause of mould, so do not rush this step. Woody herbs such as rosemary and thyme, which grow clean and upright, often need no washing at all.

Air-drying: the slow, gentle standard

Air-drying costs nothing and, for woody herbs, gives the best flavour. It is also the method most people get wrong, usually by drying in the wrong place. Skip the sunny windowsill. Light fades colour, and direct sun can cook the oils you are trying to preserve. Instead, find a warm, dry, airy room out of direct light — a spare bedroom, a loft, or an airing cupboard with the door left ajar. Moving air is what actually dries the herbs, so a gentle draught is your friend.

Two ways to air-dry

• Bundles: gather four to six stems into a bunch, tie with string, and hang upside down from a hook, a rack or a clothes airer. Leave space between bunches so air can move. String is easier than elastic bands, which perish and snap.
• Screens: for soft herbs and loose leaves, spread them in a single layer on a muslin-covered frame, a clean cake cooling rack, or a tray lined with paper. Turn them every day or two so they dry evenly.

Bundles of thyme, rosemary, oregano, sage and bay are usually ready in one to two weeks. Soft herbs such as parsley, dill, mint and chives dry in a few days on screens, but they mould quickly if left in a thick pile. Basil is the awkward one: it browns and loses much of its scent when air-dried, so use it fresh, freeze it in oil, or dry it fast in a dehydrator.

You will know they are done when the leaves feel crisp and rustle, and a stem snaps rather than bends. If a stem bends, give it more time. Under-dried herbs will go mouldy in the jar, and that is a batch you cannot rescue.

Oven-drying: quick, but easy to overdo

The oven is the fallback when the weather is damp or you need the space back. It is also the least forgiving, because most ovens do not go low enough and the herbs end up sitting in a blast of heat.

Set the oven to its lowest setting, ideally around 40°C. If yours starts higher, prop the door open with a wooden spoon to let some heat escape. Spread the herbs in a single layer on a lined tray, never on top of each other, and check after twenty minutes, then every ten. Oven-dried herbs are finished when they are brittle but still hold their colour. Take them out the moment they are crisp; a few extra minutes turns green to brown and scent to dust. Woody herbs cope far better than soft ones here, so this is not the method for basil, chervil or tarragon.

Dehydrator: the most consistent results

If you dry a lot of herbs, a dehydrator earns its shelf space. The low, steady, circulating heat dries evenly and quickly, and the trays keep leaves from clumping together. Set it to roughly 35–40°C for soft herbs and 40–45°C for woody ones, and check every half hour after the first hour. Most herbs are done in two to four hours. Keep the temperature low: turning it up saves little time and costs you aroma.

Which method suits which herb

• Rosemary, thyme, oregano, sage, bay and marjoram — air-dry in bundles.
• Parsley, dill, mint, chives, tarragon and chervil — screens or a dehydrator.
• Basil, coriander leaf and lovage — freeze or use fresh; dry only in a dehydrator, and expect a paler result.

Keeping colour and aroma

Three things rob dried herbs of quality: heat, light and air. Keep drying temperatures low, dry in the dark, and store in glass jars with tight-fitting lids away from the cooker and the window. Whole leaves hold their scent far longer than crushed ones, so leave them intact and crumble them over the pan as you cook. If you are drying a large batch, strip the leaves from the stems once they are brittle and discard the stalks — they add bulk and little else.

Label each jar with the herb's name and the month you dried it. Most dried herbs are at their best within a year; after that they are not harmful, just dull. If a jar smells of almost nothing, that is your signal to be more generous with next summer's crop.

Start with what you already grow

Drying herbs is a habit rather than a project. Begin with two or three you use most often, air-dry them somewhere you will walk past every day, and pay attention to what worked. Add a dehydrator only if you find yourself with more than you can hang. Within a season you will know your own kitchen's best spot, and how long your particular thyme takes. The reward is a shelf of jars that smell like the garden in July — and a winter kitchen that tastes considerably better for it.

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