Tea storage should be airtight to keep it fresh.
Tea is very hygroscopic (readily absorbs moisture) in nature. Therefore, if exposed to atmospheric air, it will absorb moisture, resulting in a rapid deterioration in quality and taste. In addition, tea could absorb volatile compounds in atmospheric air, resulting in masking the real flavor and aroma of tea.
Scientific studies have shown that during the storage of tea, the catechins and theaflavins are converted to thearubigins due to residual enzyme activity. This will result in a “flat” taste and a reduction of brightness in the liquor.
Breakdown of lipids during the storage of tea results in the liberation of free fatty acids. The oxidation of free fatty acids during brewing causes rancidity and an “off flavor” in tea.
Rates of reaction in the above directly correlate with the moisture content and storage temperature of the tea.
Higher moisture content and higher temperatures will lead to rapid reactions and rapid deterioration of tea. In addition, high moisture levels will also increase microbial activity, leading to undesirable ‘taints’.
Exposure to light will also lead to what is called “non-enzymatic browning reactions. This results in the dull appearance of the tea.
Therefore, using packing material that excludes light is also essential.
When tea comes out of the drier (the last stage in processing), the moisture content is reduced to 3–5%. The above reactions will take place at minimum rates at this moisture level.
Airtight packaging with material that does not allow light to penetrate and rapid dispatch to the consumer will ensure that the freshness of tea is preserved. Ideal conditions for storing tea are at low temperatures in a refrigerator with such packaging.
Once a pack is opened, storing it at a low temperature in an odorless, airtight container that does not allow light to penetrate will ensure that the freshness of the tea is preserved.