It is important to pick herbs before they flower unless you are drying the flowers themselves in which case you have to wait until they are open. The oil heavy herbs such as mint aren’t usually recommended for air drying as they can become mouldy but it can be done in the right conditions.
Cut herbs so that after discarding the leaves you can’t use they will have longish stems. With herbs with woody stems you need to cut the fleshy part of the stem, i.e. before it becomes woody. This is fairly easy during the growing season.
Discard any leaves that are damaged or marked. This will help you to dry good quality herbs and also give you the length of the stem that you need to successfully air dry. Cut the stem to the fleshy part and lightly rinse the herbs in cold water. Dry carefully and thoroughly blotting with kitchen towel.
Prepare a clean paper bag by cutting with scissors to make slits in it. These improvised holes provide ventilation and also means you can check on the herbs without having to untie the whole parcel. Drying within a paper bag ensures that any dust in the air doesn’t settle on the herbs and if leaves fall from the stem they fall into the bag and not onto the floor.
Keeping the bag as “puffed up” as possible tie string around the top of the bag so that it holds the stems in place. If the string crushes the leaves then they’re too close to the end of the stem. You should have something that looks like this photo.
The bags need to be hung in a place that is dry and where they won’t be unduly disturbed for the whole of the drying process. An airing cupboard is a good place. The warmer the place the quicker the drying process. Mint, lemon verbena and other similar herbs will dry quickly in a warm place and the woodier herbs such as sage and rosemary will take longer. Using the slits in the bag to monitor progress means that you can see easily when they’re ready to store.
When they are thoroughly dried, about 10 days to 3 weeks for mint, longer for woodier herbs depending on the warmth of the air in the drying area, store the leaves whole in an air tight container (glass is best) in a cool, dry place. Crumble the leaves as needed and remember that you only need about one third of dried herbs than you would need fresh.
An alternative to drying the oilier herbs is to cut the stem to the fleshy part and lightly rinse the herbs in cold water. Dry carefully and thoroughly blotting with kitchen towel. While preheating an oven to 150C place the herbs on a sheet of baking parchment or greaseproof paper. Leave in the oven for 90 minutes and then check the drying process. The smell in the kitchen when you are doing this is amazing.
Should you have an air dryer for using with other foods you can dry herbs successfully in it.
Note: Apolgies for the poor quality of the photos. I took them many years ago and had to resort taking photos of them on my computer screen as I couldn’t find the originals!