Keep them at 35 to 40 C, out of the light, and store them whole. Most home dried herbs taste of nothing because they were dried too hot.
What you are trying not to drive off
The flavour in herbs is in volatile oils, and volatile means exactly what it sounds like: they leave with the heat. Water leaves at any temperature given airflow, so there is nothing to gain by turning the dial up.
Dry basil at 60 C and you get green confetti with no smell. Dry it at 38 C and the jar smells like the plant when you open it a year later.
Temperature and time
| Herb | Temperature | Time |
|---|---|---|
| Basil | 35 to 38 C | 3 to 5 h |
| Parsley, coriander | 38 to 40 C | 3 to 5 h |
| Mint | 38 to 40 C | 3 to 5 h |
| Oregano, thyme | 40 C | 2 to 4 h |
| Rosemary, sage | 40 C | 3 to 5 h |
| Bay leaves | 40 C | 4 to 6 h |
| Chives | 35 C | 2 to 4 h |
Stems or stripped leaves
Dry small leaved herbs like thyme and oregano on the stem and strip them afterwards. It is far quicker and the leaves come off cleanly once brittle.
Strip large leaved herbs like basil and sage first, so the leaves lie flat and dry evenly. Whole stems of basil hold moisture at the base long after the leaves are done.
Light and colour
Light bleaches herbs and degrades the same oils heat does. Dry them somewhere out of direct sun, and store the jar in a cupboard rather than on a spice rack by the window.
Good colour is a fair proxy for good flavour. Grey green dried basil has usually been cooked.
Storage
Store whole leaves and crush them as you use them. The oils sit in intact cells, and grinding releases them into the air of the jar rather than into your food.
A sealed jar in a dark cupboard holds usable flavour for about a year. Ground herbs from the same batch lose it in three or four months.
Questions people ask
What temperature ruins the flavour? Anything much above 40 C starts costing you noticeably.
How long do dried herbs keep their flavour? Around a year whole, a few months ground.
Should you dry on the stem? Yes for small leaved herbs, no for large soft leaves.
Safety note. Wash and dry herbs thoroughly before drying, especially anything grown at ground level. Dry herbs are shelf stable, but a wet stem sealed into a jar will mould.
What this is based on
- National Center for Home Food Preservation, drying herbs
- University extension publications on herb drying temperatures
- Manufacturer temperature guidance for herb settings