Freshness of tea and storage

Air tight packaging for freshness of tea storage

Tea is very hygroscopic (readily absorbs moisture) in nature. Therefore, if exposed to atmospheric air it will absorb moisture resulting in rapid deterioration in quality and taste.

In addition, tea could absorb volatile compounds in atmospheric air resulting in masking the real flavour 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 reduction of brightness in the liquor.

Breakdown of lipids during storage of tea results in the liberation of free fatty acids. Oxidation of free fatty acids on brewing leads to rancidity and ‘off taste’ in tea.
Rates of reaction in the above have a direct correlation with the moisture content and storage temperature of tea.

Higher moisture contents and higher temperatures will lead to rapid reactions and rapid deterioration of tea. In addition, high moisture levels will also increase the microbial activity leading to undesirable ‘taints’.
Exposure to light will also lead to what is called ‘non-enzymatic browning reactions’. This results in a duller appearance of tea.

Therefore, using packing material that excludes light is also important.
When tea comes out of the drier (the last stage in processing) the moisture content is reduced to 3-4%. At this moisture level, the above reactions will take place at minimum rates.

Air tight packaging with material that does not allow light to penetrate and rapid dispatch to the consumer will ensure that freshness of tea is preserved. Ideal conditions for storing tea are at low temperatures in a refrigerator under such packaging.
Once a pack is opened, storing at low temperature in an odourless airtight container which does not allow light to penetrate will ensure that freshness of tea is preserved.