Xiao understands that tea friends have asked a question these two days, saying that they have stored tea cakes for several years, and there are spots of oil stains on them, is it damp? Or is tea like a human, and it becomes greasy in middle age? Can I still want this tea?
In fact, do not get damp, open the tea cake to smell whether there is a peculiar smell, and see if the cord has become soft.
If it is not damp, it is the "tea oil" that appears on the Pu'er tea cake. The so-called "tea oil" refers to the yellow oil stains that appear on the cotton paper after several years of storage of Pu'er tea.
So, why does Pu'er tea appear oil stains after storage?
Pectin substance exudation
Pu'er tea is made from Yunnan large-leaf seed sun-dried green tea as raw material, and the content is relatively rich. In the long-term storage process, after the cell wall of Pu'er tea is ruptured, the pectin substances contained in it will be decomposed into soluble hydrated pectin, which will gradually exude and be adsorbed onto the cotton paper, and gradually form tea oil.
It should be noted that the "tea oil" on the cotton paper of Pu'er tea packaging is different from the edible Pu'er tea oil. Pu-erh tea oil is made from Pu-erh tea fruit, the main ingredient is fat, while tea oil on packaging cotton paper is not fat.
Volatile oil
Pu'er tea volatile oil contains more than 50 kinds of containing substances such as alcohols, aldehydes, aromas, esters, etc., and tea oil is also related to these volatile oil substances.
The volatile oil composition of Pu'er tea also has a certain relationship with the aroma. This is also why after pu-erh tea is stored, the aroma will gradually change. Among them, the phenols will degrade, and the axogenous compounds will increase, so that in the later stage, the aroma of dry tea will gradually disappear, and it needs to be brewed to brew out the aroma.
storage
The tea oil of Pu'er tea has little to do with Taiwanese tea and ancient tree tea, but it has a lot to do with the storage environment. If the storage environment temperature is too high, the air is relatively non-circulating, coupled with the alternating weather dry and wet, it will stimulate the decrease of thearubicin and theaflavin in the tea cake, the theaflamin increases, and the contents will also ooze out onto the cotton paper, which will be prone to tea oil.
And when stored, Pu'er tea is often stacked in its entirety, resulting in mutual squeezing between tea and tea, coupled with strong adsorption of cotton paper, so the storage time is long, and tea oil will also penetrate into cotton paper.
In summary, the appearance of tea oil on cotton paper is a normal phenomenon that occurs during the aging and storage process of Pu'er tea, and has nothing to do with the quality of tea.
And the tea is properly stored, there is no mold, odor, the appearance of tea oil tea cake, smell often more aromatic, tea soup taste is not inferior.
However, this kind of tea is not perfect in appearance, so the price will be relatively cheaper, if it is self-drinking, it is no problem at all. But if it's an investment, think about it.