【The Role of Tea Stems】Aroma compounds in tea are mainly present in the stems and main veins of young leaves. The aroma intensity decreases from the first to the third leaf, while tea stems contain the highest concentration of these aromatic substances. Because young stems have more aroma compounds than young leaves, compressed teas like Pu'er always include some stems. Firstly, this creates appropriate gaps to facilitate later fermentation; secondly, the stems contain a considerable amount of aroma substances, making them essential for producing fragrant and flavorful high-quality tea.