Dried herbal blends keep best in airtight, dark, cool and dry conditions. Keep this tea in its original packet if it reseals reliably, or transfer it to a clean, dry tin or jar with a tight-fitting lid. Place it in a cupboard away from direct sunlight, radiators, the stove and other sources of heat or moisture; a cabinet that is not directly above the oven or dishwasher is usually a safe spot.
Moisture affects dried herbs faster than almost anything else. Repeated exposure to steam or a wet spoon can make the leaves lose aroma or spoil before the best-before date, so always use a dry spoon or scoop, close the container immediately after use, and never add water to the packet. Strong smells are another factor: dried plant material absorbs surrounding odours, so keeping the tea away from spices, coffee and strongly scented household products helps preserve its own aroma.
How long an opened packet stays at its best depends on how it is stored. Rely on the best-before date on the label and on your senses: fresh tea smells aromatic and feels dry; if the aroma has faded, or the leaves feel damp or smell musty, it is better to replace it. Stored properly, a 50 g packet keeps its character for a long time.