China Tea Network news: Quality changes during tea storage mainly manifest as: increased moisture content in tea leaves, reduction of flavor compounds, deterioration of aroma, and darkening of tea leaves and liquor color. The primary factors causing these changes are moisture, temperature, oxygen, light, and odors. Although the health benefits of tea are significant, the following points should be noted when storing green tea:

1. Avoid moisture: Green tea leaves are a porous hydrophilic substance with strong moisture absorption properties. The relative humidity should be around 60% for storage; exceeding 70% may cause mold spots and acidification due to moisture absorption.

2. Avoid sunlight: Sunlight promotes the oxidation of pigments and esters in green tea, decomposing chlorophyll into pheophytin. Storing green tea in glass containers or transparent plastic bags exposed to sunlight triggers chemical reactions that degrade tea quality.

3. Avoid oxygen: Chlorophyll, aldehydes, esters, vitamin C, etc., in green tea easily combine with oxygen in the air. Oxidized green tea results in darker liquor and significantly reduced nutritional value.

4. Avoid high temperatures: The optimal storage temperature for green tea is 0–5°C. High temperatures break down amino acids, sugars, vitamins, and aromatic compounds, diminishing quality, aroma, and taste. High temperatures accelerate chlorophyll degradation, converting it to pheophytin and turning vibrant green into dull brown. The auto-oxidation of compounds like tea polyphenols also intensifies. Studies show that for every 10°C increase in temperature, the browning rate of green tea accelerates 3–5 times, leading to aging and spoilage.

5. Avoid odors: Green tea contains highly reactive macromolecular palmitase and terpenoids that readily absorb odors. If stored with odorous items, the tea will absorb these smells and cannot be rid of them.