1. Look at the tenderness of the tea leaves.
In principle, teas made from older leaves get better with age, while teas made from tender buds are better when fresh. White tea is a perfect example:
1) Shou Mei white tea, mainly made from older leaves, is rich in substances. Through aging, some astringent and stimulating compounds gradually mellow, becoming purer over time and developing aromas like bamboo leaves.
2) Bai Hao Yin Zhen, made from tender buds through natural withering, is best enjoyed for its fresh, brisk flavor. Aged Bai Hao Yin Zhen becomes thin in taste; aging doesn't enhance its quality, so it's better to drink it fresh.
3) Bai Mu Dan, made from one bud and two leaves, falls between Shou Mei and Bai Hao Yin Zhen. Both fresh and aged versions have their own distinct styles.
2. Look at the fermentation process.
In principle, non-fermented and fully fermented teas are better when fresh; lightly fermented and semi-fermented teas have their merits both fresh and aged; post-fermented teas taste better aged. This is due to the role microorganisms play in the transformation process.
1) Non-fermented teas, like green tea, are quickly heated at high temperatures to preserve amino acids, vitamins, and aromatic compounds. A side effect is that microorganisms are mostly killed. Without microbial activity, these compounds diminish over time, making fresh tea preferable.
2) Fully fermented teas, like black tea, undergo complete oxidation of active compounds, leaving little for microorganisms to transform. Aging offers no benefit. Considering the time needed for the 'fire qi' to dissipate, black tea is generally best consumed within six months to a year.
3) Lightly and semi-fermented teas, like Tie Guan Yin, often have better aroma when fresh, but some aged teas can develop richer, more mellow flavors. Their semi-fermented nature gives them characteristics of both green and black tea, allowing some microbial transformation. Thus, both fresh and aged versions have their appeal, depending on personal taste.
4) Post-fermented teas, like Pu-erh, rely entirely on microbial activity for transformation, so they improve with age. However, there are limits; all foods have a shelf life. Generally, ripe Pu-erh's drinking quality declines after about 20 years. Raw Pu-erh can age longer, but beyond 40 years, the aged flavor increases while richness decreases, becoming increasingly bland—only a historical relic.
3. Look at the storage method.
Different tea types require different storage methods, but the following points are essential:
1) Dryness. Damp environments can foster harmful molds like aflatoxin, making such aged tea harmful and unfit for consumption.
2) Tea must be isolated from contamination yet able to breathe, providing a suitable environment for microorganisms. For example, Pu-erh shouldn't be refrigerated or sealed in plastic bags. It's best wrapped in rice paper and stored in a ventilated place, using bamboo husk packaging or unglazed purple clay jars.
3) Due to tea's strong absorbency, it must not be stored near odors, or it will absorb them over time, becoming worse with age.
Of course, these are general principles; exceptions always exist. Next time you encounter aged tea, don't be 'deceived'!
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