The most common way to preserve herbs is to dry them. This method is perfect for many common herbs. There are other techniques, however, which are more appropriate to particular herbs to preserve their qualities more effectively.
Drying in Trays
Drying eliminates the water in the herb but retains its essential oils. Whichever drying method you use, herbs should be dried quickly at an even temperature, out of direct sunlight. The air must be able to circulate around the herbs and it is best to keep individual herbs separate as they are drying.
To dry herbs naturally, spread the herb sprigs, roots, petals or seed heads evenly over trays lined with sheets of absorbent paper, such as newspaper. For larger leafed plants, such as lovage and comfrey, remove the leaves form the sprigs before you dry them. Leave the herbs for a week or so until completely dry, turning them regularly and replacing the paper if it absorbs too much moisture. Roots will take a little longer.
If you dry herbs regularly, it is worth making a drying frame. Stretch muslin (cheesecloth) or fine netting over a rectangular wooden frame and lay the herbs on the frame to dry. The frames can be stacked on top of on another as long as there is about 2 inches between them. Place newer herbs on top of the drier ones as the moisture will rise.
You can speed up the drying process by placing the trays or frames in a warm airing cupboard for three or four days. Alternatively, you can dry them in the plate-warming section of a cooker or at the bottom of a conventional over with the door agar, leaving the oven on its lowest setting for a few hours. If you have a traditional fuel-burning stove, you can dry the herbs in the slow oven.
One modern method is to use the microwave, which I tend to not recommend due to the uneven drying process..However, if you would like to try this method, spread out the herbs on three layers of paper towels and cover with another sheet of paper towel. The herbs will take only 2-3 minutes on high, but will be ruined if you leave them too long. Therefore it is best to microwave for 30 seconds, check and turn them over, then continue in short bursts until they are dry.
The most modern method is the dehydrator, which I tend to use most often in the winter months. You will want to remember to check your herbs frequently and rotate the trays accordingly.
Drying in Bunches
Herb flowers, such as chamomile, feverfew, lavender, sorrel or tansy, sprigs such as rosemary, sage or bay, or seed heads such as fennel, can be air-dried in bunches. Tie four or five herb sprigs loosely into a bunch by the stems and hang them upside-down in a dry, well-ventilated room where the temperature remains constant, keeping them out of direct sunlight. A spare room, dry attic or a bedroom are all suitable.
When drying herbs with large flower heads, such as chives, the flowers must rest on a wire mesh screen with the stems hanging down, as the drying stems cannot stand the weight of the flower heads. Large seed heads, such as fennel, lovage, caraway or chervil, or large herbs such as angelica, can be dried upright in empty vases.
Preparing and Storing Dried Herbs
Once the herbs are dry, they will feel crisp and papery and will snap easily between finger and thumb. Then remove the leaves from small-leafed herbs, run your fingers down the stalks and the leaves will rub off. For herbs, the larger leaves, you may need to hand-pick the leaves from the stalks then crumble them between your fingers, or place the leaves in a paper bag and crush them with a rolling pin. Another method is to rub the herbs through a fine mesh before discarding the stems.
Dried herbs must be stored in airtight containers, preferable in a dark cupboard. The containers should be labeled wiht the name of the herb and the date of preserving. Even dried herbs will not keep indefinitely so do not dry in larger quantifies than you are likely to use.
Seeds can simply be shaken off the dried flower heads then sieved or hand-picked to remove unwanted chaff. If you are storing them for planting the following season, wrap them in foil and then seal in an envelope labeled with the name of the seed, the date of collection and any other details such as the variety or flower color. Seeds for culinary use can be stored in an airtight jar, labeled with the name of the seed and date of preserving and kept in a dark cupboard.
To preserve complete flower heads for dried arrangements or to garnish potpourri, desiccants are used; these are crystals that absorb moistures from a flower while preserving its shape. The easiest to use is silica gel, which you can buy from the most craft stores. Grind it down in a food processor or with a pestle and mortar until it is as fine as caster (superfine) sugar.
Spread a layer of desiccant in the bottom of a plastic box. Arrange the flower heads on the surface and cover with desiccant gently, sprinkling it between the petals. Dry bell-shaped flowers upside down so that the bells fill with desiccant. Seal the box and leave it undisturbed for five days, during which time the silica crystals will turn from blue to pink. Brush off a little of the desiccant and if the flowers are dry and make a rustling, papery sound when moved, remove them from the box and brush them clean.
Bend a small hook at the end of a piece of florist’s (floral) wire and push it through the flower head, pulling it back to secure it. Wind gutta-percha tape diagonally around the stem to cover the wire and store the delicate flowers upright in dry florist’s foam (Styrofoam).
Reactivate the desiccant by spreading it on a baking sheet and placing it at the bottom of a low oven until its color turns back to blue. Sieve it to remove any particles and store for future use.
Kali S. Winters