In Green Tea, there is a saying that “pre-Ming Tea is as precious as gold,” indicating that fresh pre-Ming tea has a mellow and smooth taste and a very fresh and refreshing flavor. However, when new tea hits the market each year, some unscrupulous vendors may take the opportunity to pass off old tea as new. Therefore, it is very important to know how to distinguish between fresh and old tea. So, what are the methods? Let's take a look together!
1. **Observe the color**
During the storage of tea leaves, pigments that constitute the tea's color undergo slow automatic decomposition due to the effects of oxygen in the air and light. For example, the decomposition of chlorophyll in green tea gradually changes its color from the fresh, verdant green of new tea to a yellowish-green and dull gray. The oxidation of ascorbic acid (Vitamin C) present in high amounts in green tea produces brown pigments, which can make the tea infusion appear yellowish-brown.
In general, new tea leaves are usually bright and lustrous, with good smoothness, and the tea infusion has a relatively clear and bright color. In contrast, old tea has a slightly darker hue and is less smooth.
2. **Taste the flavor**
When buying tea, it is essential to taste the infusion yourself, as this is the most direct method to distinguish between fresh and old tea. From the perspective of taste, new tea generally has a relatively fresh and brisk flavor, whereas old tea becomes thinner due to the oxidation of esters in the tea leaves, which results in the formation of volatile aldehydes or insoluble condensation products. This leads to a reduction in Water-soluble components, making the taste less rich. Additionally, the oxidation and deamination of amino acids in the tea leaves weaken the fresh and brisk taste, making it duller.
3. **Smell the aroma**
The aroma of fresh tea tends to be more persistent, while old tea becomes dull due to the oxidation, condensation, and slow evaporation of aromatic compounds. Scientific analysis shows that over 300 compounds contribute to the aroma of tea, mainly alcohols, esters, and aldehydes. These compounds can both evaporate and slowly oxidize during storage. As time passes, the aroma of tea gradually fades from being strong and fragrant to becoming dull and low.
4. **Check the Humidity**
New tea is drier, while old tea is moister. New tea, having just been processed, has a lower moisture content and feels dry. Old tea, stored for a longer period, has a higher moisture content. When you squeeze the tea leaves, new tea crumbles into powder easily and the stems break readily, whereas old tea feels soft, does not crumble into powder, and the stems are harder to break.