Puer Tea Sealed Storage Experiment
Sealed storage of Puer tea inevitably involves the issue of oxygen supply in the warehouse. According to post-Fermentation theory, Puer tea requires oxygen and a certain level of Humidity for post-fermentation, so the tea storage warehouse needs to be ventilated to allow the tea to undergo post-fermentation.
However, many people have found that when tea is stored under ventilated conditions, while the Infusion color turns red, it loses its aroma after two or three years, and the bitterness and astringency do not diminish over time. Additionally, under ventilated conditions, the tea's aroma naturally cannot be preserved. In fact, the later changes in Puer tea are influenced by two factors: one is microbial fermentation, which is an external effect; the other is the action of active enzymes within the tea leaves, which is an internal effect. After sealing and controlling the humidity, Puer tea does not require microbial fermentation, but instead relies primarily on the active enzymes present in the tea to facilitate its transformation.
When storing tea in a sealed and oxygen-deprived environment, how would Puer tea change? This question led me to conduct an experiment on the effects of oxygen in sealed storage.
Experimental Method: Take Puer tea from the same year and made using the same process from the Jingmai Mountain ancient tea trees. Divide the tea into four equal portions and store them using four different methods. One portion is vacuum-sealed, another is placed in a sealed Bag, a third is placed in a sealed bag with periodic oxygen addition, and the fourth is stored naturally without sealing. All four portions of tea are stored in the same tea warehouse equipped with a dehumidifier. After four years, they are brewed and compared. For each portion, use 3 grams of tea, 150 grams of water, and steep for 5 minutes. The results are as follows ——
Vacuum-Sealed Storage: The best change in infusion color, presenting a golden-red hue. The aroma of the tea is preserved well, with both the dry tea and tea infusion having a significantly higher aroma than fresh tea. The tea infusion has a distinct aroma. However, the bitterness does not recede well, making it the most bitter among the four samples.
Sealed Without Vacuum: Good change in infusion color, presenting a golden-red hue. The aroma of the tea is well-preserved, with both the dry tea and tea infusion having a significantly higher aroma than fresh tea. The tea infusion has a distinct aroma, second only to the vacuum-sealed sample. Bitterness and astringency are noticeably reduced.
Sealed With Oxygen Addition: The infusion color presents as golden yellow, showing less change than the first two samples. The tea has an aroma, but it is clearly less pronounced than the first two. Bitterness and astringency decrease, more so than in the vacuum-sealed sample, but similar to the sealed without vacuum sample.
Naturally Stored Without Sealing: The infusion color presents as golden yellow, similar to the sealed with oxygen addition sample. The tea has lost most of its aroma. There is a slight hint of transformation flavor. Bitterness and astringency decrease, but to a lesser extent than in the sealed samples.
The Leaf base colors of the four teas show no significant differences.
Since this experiment lasted only four years, it is too early to draw definitive conclusions. Based on this experiment, there are several notable observations.
First, vacuum-sealed storage can preserve the characteristics of the tea well, making it suitable for storing tea samples. However, since the bitterness and astringency do not diminish well, it is not recommended as a method for storing Puer tea.
Second, the role of oxygen in the changes of Puer tea was not evident. Both the naturally stored and periodically oxygen-added tea samples showed no advantages in change compared to those stored in a sealed, nearly oxygen-free environment.
Third, sealed storage of Puer tea not only preserves the tea's aroma but also demonstrates the characteristic of becoming more fragrant over time.
Fourth, sealed storage of Puer tea, under the influence of the active enzymes within the tea leaves, results in a relatively rapid reduction in bitterness and astringency and a quick change in infusion color. This indicates that Puer tea can rely on its own active enzymes for transformation.
Excerpted from the magazine “Puer”
“Puer Tea Sealed vs. Ventilated Storage Comparative Experiment”
If there are any copyright issues, please contact us to remove the content.