- Tea being a hygroscopic substance, readily absorbs water from its surroundings. Tea quality deterioration on storage was found to accelerate with high relative humidity and heat and it is for this reason that storage in cool and dry conditions is essential.
- Water activity which is a measure of the free moisture in a product is one of the most critical factors responsible for the quality of tea. The water activity affects the shelf life, product quality and safety including texture, flavor & smell. The water activity may be the most influential factor for controlling tea degradation. Effect of temperature on water activity of a food is product specific. Water activity of tea has a tendency to increase with temperature. Therefore, it is required to store tea under low temperature to avoid the effect of high temperature on water activity. Ideal temperature is below 25°C and the recommended maximum temperature is 30°C
- According to the typical sorption and desorption isotherm of food, the water activity increases with the moisture content. Therefore, the relative humidity should be maintained at a lower value to prevent the increase of tea moisture. Ideal relative humidity is below 55% and the recommended maximum relative humidity is 70%
- Tea when exposed to air increases the chances of absorbing moisture and strong odour. Materials with low barrier properties such as paper bags if used during storage may also contribute to absorb moisture to tea through the packaging material. That is why it is essential to store tea in an air tight container made of suitable barrier material.
- Quality deterioration of tea stored even in air tight containers may sometimes be unavoidable if the tea is exposed to light sources, especially UV or IR radiation. Sun light degrades your tea. Excessive heat too degrades your tea very fast. That is why it is important to store your tea away from direct sun light and heat.
Facts of Tea
Why should you store tea in a cool & dry place, in an air tight container, away from light sources and heat?