Tea has strong hygroscopic and odor-absorbing properties, easily absorbing moisture and odors from the air. With slightly improper storage methods, tea can lose its flavor within a short period. The more lightly fermented and fragrant the premium tea is, the more difficult it is to preserve. Usually, after being stored for some time, the aroma, taste, and color of tea will change—the fresh tea characteristics disappear, and aged flavors gradually emerge.

Environmental factors affecting tea deterioration

The main environmental conditions affecting tea deterioration and aging are temperature, moisture, oxygen, light, and their interactions.

Temperature

Higher temperatures cause tea's appearance to turn brown more easily. Low-temperature refrigeration (freezing) can effectively slow down browning and aging.

Moisture

When the moisture content in tea exceeds 5%, it accelerates quality deterioration and promotes oxidation of residual enzymes in tea, leading to color changes.

Oxygen

Oxidation reactions causing various tea deterioration are all related to the presence of oxygen.

Light

Light exposure adversely affects tea, accelerating various chemical reactions. Chlorophyll easily fades under light exposure.

From the above, we can conclude:

Reducing storage environment temperature.

Maintaining contact between tea and oxygen.

Blocking contact between tea and oxygen.

Preventing direct light exposure can all slow down tea deterioration.

Tea storage methods

Generally, household purchased tea comes in cans or as loose tea. Since it's not consumed all at once, storage becomes an issue. Below are several commonly used household tea storage methods:

Plastic bag, aluminum foil bag storage method

Choose food-grade plastic bags with seals, preferably those with high density and thickness. Avoid using scented or recycled plastic bags. After filling with tea, squeeze out as much air as possible from the bag. Using a second plastic bag reversed over it is even better. Transparent plastic bags shouldn't be exposed to sunlight. Aluminum foil bags work on similar principles. Additionally, divide purchased tea into small packages, seal them, and store in the refrigerator. Brew in batches to reduce air exposure after opening, delaying quality deterioration.

Metal can storage method

Use iron cans, stainless steel cans, or dense tin cans. For new cans or those previously storing other items with odors, put some tea dust inside, cover, shake gently to rub the inner walls, then discard to remove odors. Two-lid stainless steel tea cans available commercially are convenient and practical. For better results, place tea in a clean, odor-free plastic bag before putting it in the can. Seal the lid with tape. Metal cans containing tea should be kept in cool places, away from direct sunlight, odors, humidity, and heat sources. This prevents rust and slows tea aging. Tin cans, with dense material, effectively block moisture, oxygen, light, and odors.

Low-temperature storage method

Keep the tea storage environment below 5°C using refrigeration or freezing. Note the following:

For storage under six months, maintaining 0-5°C refrigeration is most economical and effective; for over six months, freezing (-10 to -18°C) is better.

Dedicated冷藏(freezing) storage is ideal. If sharing with other foods, ensure tea is well-packaged and completely sealed to avoid odor absorption.

Ensure good air circulation in the冷藏(freezing) unit for effective cooling.

When buying large quantities, first divide into small packages (cans) before refrigerating (freezing). Take out only needed amounts each time; avoid repeatedly freezing and thawing the same package.

When removing tea from冷藏(freezing), let the can reach room temperature before opening. Otherwise, sudden opening may cause moisture condensation, increasing water content and accelerating deterioration of remaining tea.

Long-term tea storage treatment methods

Tea moisture content must be controlled at 3-5% for long-term storage. Roasting and drying levels significantly affect storage duration; generally, heavily roasted, low-moisture tea can be stored longer.

When tea reaches its optimal storage period, it should be taken out for re-roasting. Clean a rice cooker until odor-free, dry it, then place tea on a ceramic plate or foil inside. Set to [Keep Warm], partially cover the lid, and stir occasionally. After about half a day, when the tea turns from stale to clean roasted aroma and crushes easily between thumb and finger, let it cool before repackaging and storage.

Some use microwaves for drying/roasting tea, but heating time is short, and with the door closed, control is difficult, often leading to surface charring or trapped stale odors. This method still needs technical improvement.

The safest method is to entrust treasured tea to a familiar tea master or farmer for roasting.