- Keeping the tea in an attractive glass jar on display.
Storing tea where it may be exposed to sunlight can result in the lightening of the tea leaves. This is because the ultraviolet (UV) light breaks down the chemical components found in the tea leaves, bleaching them of any colour, as well as giving the tea a metallic flavour due to the light-induced damage. The exact reaction initiated by the sunlight is not actually known; however, many theories indicate that a combination of chemical reactions take place in the chloroplast (site of photosynthesis) and the cytoplasm (site of most cell reactions).
There are numerous ways around this issue, including simply storing the tea in a cupboard rather than on the work surface. Even well-sealed, opaque glass canisters should be stored carefully, but will serve better to preserve the life of the tea. Individually sealed tea bags with colourful foil packets are attractive and when kept in a clear glass jar away from direct sunlight can be an effective way to keep the tea relatively fresh.
- Allowing a tea jar to reach the bottom before refilling.
As the amount of tea, loose-leaf or in a tea bag, decreases in the jar the amount of air inside the jar increases. This can become a problem because over time tea leaves continue to oxidise, despite being slowed due to the heating process all tea undergoes, with exposure to oxygen. With less tea in the container the deterioration speeds up, whilst when full the process is slowed. As the tea oxidises it will lose a large amount of its flavour before becoming noticeably stale. Impurities, such as dust, and increased moisture content, can cause the tea to develop an unpleasant flavour, due to the exposure to air.
Airtight vessels minimise the amount of air present when full, but some ambient air remains in between the tea leaves – airtight is not the same as air-free. For this reason, when trying to keep your tea fresh maintaining a full container is imperative, whether its tea bags or loose-leaf. Some retailers will vacuum seal airtight, food-grade pouches for the tea; this is an excellent way for it to be bought if it is likely to remain unopened for a long time, and its shelf life can be extended through freezing but only when vacuum packed.
The only exception to this is Pu’er tea, as it needs access to some air in order to properly age. It should, therefore, be stored in a breathable container, such as fabric.
- Storing the tea above the kitchen stove or hob in a cupboard.
Some of the more delicate teas, such as green and yellow, are best when stored in the freezer or fridge.
- Stowing tea next to your kettle in easy reach
- Storing tea next to spices.
As a quick tip, teas that are less oxidised (greens, yellows and whites) degrade faster than their more oxidised equivalents (oolongs and blacks). Also, tea leaves that are more broken down have a higher surface area in contact with air, so will deteriorate faster.