White teas like Bai Hao Yin Zhen (Silver Needle), Bai Mu Dan (White Peony), and Shou Mei are picked from the youngest to oldest leaves. Younger doesn't mean better, they just have different flavors. It's less common to find aged Silver Needle or White Peony. Shou Mei, however, is the best type for aging into “Lao Bai Cha”
(Aged White Tea). That's why most aged white tea
you find in stores is Shou Mei.

Shou Mei has fewer buds, more large leaves, and includes some tea stems. This might look rough compared to delicate teas, but it actually helps
it change faster and more noticeably during aging. Older leaves and stems are packed with more natural compounds that help this transformation.

If you compare tea cakes, Shou Mei ages much quicker than Silver Needle or White Peony. The stems play a key role. They create small air pockets inside the pressed cake. Tiny channels inside the stems let tiny amounts of air reach the tea inside the cake. Since aging white tea needs just a little oxygen, these stem channels allow the whole cake – inside and out – to age slowly and evenly together.

As Shou Mei ages over years: Levels of some compounds (like polyphenols, caffeine, and sugars) slowly go down. Levels of beneficial flavonoids steadily go up. This gradual change makes aged Shou Mei suitable and enjoyable for more people.