Pu-erh tea is a type of fermented tea that undergoes a natural or artificial aging process. There is a misconception that all pu-erh teas benefit from aging, but just like with wine, some types of pu-erh tea age better than others. The quality of the leaves, the type of fermentation process used, and the storage conditions are important factors that determine the aging potential of pu-erh tea.
Aging Potential of Mao Cha
Mao cha is the processed pu-erh tea leaf that is either green or ripe. It is available in loose-leaf form or pressed into shapes like cakes or beengchas. The better quality green mao cha pressed into cakes is usually the ideal candidate for a long aging process of up to 30+ years. On the other hand, it is a rare cooked or ripe pu-erh that merits aging past ten years. Most ripe or cooked tea of average quality leaf is consumed immediately after processing as aging is of little help to the taste. There is considerable controversy over the aging process surrounding ripe or cooked pu-erh.
Factors Affecting Aging Process
After picking, pu-erh leaves are turned into mao cha by a short process referred to as “kill green.” The leaves can be artificially aged by a six-month to a year-long fermentation procedure called wo dui or pressed into cakes and stored for natural aging. Virtually all mao cha can benefit from at least a short aging process, with some pu-erh aficionados feeling that cooked pu-erh should not be aged over ten years.
Environmental factors surrounding the tea’s storage will affect how quickly and successfully a tea ages. The tea must be stored away from any strong odors lest they acquire them, sometimes permanently. Airflow regulates the oxygen content surrounding the tea and removes odors from the aging tea. Humidity is a factor, with the higher the humidity, the faster the tea will age. However, water accumulating on the tea causes the growth of mold or can dilute the flavor of the tea so is to be avoided. Humidity in the range of 60-85% is optimal for the aging process. Sunlight has an adverse effect on tea, causing it to become bitter and prematurely dries out the leaves. In addition, tea should not be subjected to high heat since undesirable flavors will develop. On the other hand, at low temperatures, the aging of pu-erh tea will slow down dramatically. Some believe that tea quality is adversely affected if it is subjected to highly fluctuating temperatures or humidity.
Sampling Pu-erh Tea
Ultimately, one will have to sample the tea to determine how much a particular cake is benefiting from the aging process. To arrest the aging process, wrap the tea in shrink-wrap or plastic (some say tightly fitting glass is best), store it properly, and enjoy drinking it at one’s leisure.
Comparison with Wine
Some wines benefit more from aging than others. Generally, reds are better candidates for aging than whites, and most wines reach their aging peak in three to seven years, with fifteen years usually being the maximum except for a few very expensive German Rieslings. Similarly, with pu-erh tea, the aging potential varies depending on the quality of the leaves, the type of fermentation process used, and the storage conditions. Therefore, just like with wine, it is important to consider these factors when planning the aging of pu-erh tea.