The so-called resistance to brewing means that after multiple infusions, the tea's color and taste do not change significantly. Pu'er tea is indeed highly resistant to multiple infusions. In fact, what we see is only the surface; the reason it is so resistant lies in the substances contained within the tea.
Arbor Pu'er tea trees have undergone centuries or even thousands of years of growth, accumulating rich nutrients in their leaves and buds. When consumed, these nutrients require many infusions to be fully released, which is why we perceive it as being highly resistant to multiple brews.
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