Even if you buy the highest possible quality tea, if you don't store it well, you will just waste your tea and money because the tea will lose its color, aroma and taste. Why does that happen and how should we store tea properly?
First of all, please allow me to explain some important characteristics of tea.
- Tea is good at absorbing moisture.
- Tea is good at absorbing odors.
- Tea is easily oxidized (i.e. it is a fresh product that can become stale).
more quickly at higher temperatures or in a moist environment.
Secondly, let's analyze the factors influencing quality during tea storage.
The quality of tea deteriorates more rapidly at higher temperatures. Tests have shown that an increase in temperature of 10℃(50℉) causes an increase of 3-5 times in the rate of discoloration of tea due to oxidation. This is because the chlorophyll in tea easily breaks down when exposed to heat and light. Refrigeration is a good way to prevent this kind of deterioration.
When the moisture of tea increases, chemical components such as polyphenols and chlorophyll will break down more rapidly. It also creates an environment more attractive to mold, which of course accelerates decomposition. To prevent this the moisture content of tea should be kept below 5%. Accordingly, if you refrigerate your tea, don't let any moisture (e.g. condensation) inside the package.
Roughly 20% of the air we breathe is oxygen, so if tea is left unsealed, exposure to air will speed up oxidization. Store tea in a container with an airtight seal.
Light also speeds up the chemical reactions in tea; when exposed to sunlight, tea will develop a stale taint and deteriorate more quickly. Tea should be stored in an opaque container.
To summarize, proper storage of tea has two fundamental requirements: first, a dry place; second, a temperature no higher than 5 ℃. The key to keep your tea as fresh as possible is to seal it in an airtight bag or in a jar/container and save it in a clean, dry, cool and dark place. It is good to store tea in the refrigerator (-4℃to 2℃), but you must make certain it is not exposed to other odors inside the refrigerator - this is especially true for a high quality green tea. In addition, a large quantity of tea should be divided into small packages, which can then be vacuum sealed. Black or oolong teas stored in a sealed package at a low temperature will keep for one to two years (although very delicate green teas won't last that long - a year is about the longest they'll last).
Of course, if you drink tea every day like me, you can simply finish it all before it goes bad. :P