What Is White Tea

White tea is the least-processed of the tea classes. It is not rolled, not fired, not shaped, and not fixed by the pan-firing other classes use to halt their enzymes. It is made from the buds, leaves, or tender shoots of Camellia sinensis and reaches finished tea through two operations: withering (weidiao 萎凋) and drying (ganzao 干燥), with a sorting-and-picking step (jianti 拣剔) between the leaf and the tin.

Those two operations, plus the sort, are the entire process. What distinguishes white tea from every other class is how little is done to the leaf between the branch and the tin.

The subject is governed by a national standard, GB/T 22291-2017¹, which defines white tea as a product made by withering, drying, and sorting, and sets out four products along a descending bud-to-leaf ratio. Its home is Fujian province, in the counties of Fuding and Zhenghe.

The two steps, and what is withheld

Withering is the key stage. It runs long: commonly 24 to 72 hours, the exact span read from the weather. Oolong and black tea also begin with a wither, but a far shorter one, before the leaf is worked further. In white tea the wither itself does most of the work, and drying only finishes it.

As the leaf loses moisture, its cell walls break down and release oxidase enzymes, polyphenol oxidase and peroxidase among them. These drive a slow, light oxidation, on the order of about 5 percent⁵, with no deliberate oxidation step anywhere in the process. Roughly 172 volatile compounds⁴ are formed or modified while the leaf withers. So white tea is not "unoxidized."

Then the leaf is dried, and sorted, and it is finished.

There is no fixation, the kill-green step that other classes apply to stop the enzymes cold. There is no rolling, which would break the leaf and rub the down from the bud. There is no shaping. Because so little happens to the leaf, it keeps a high concentration of catechins and other phenolic compounds relative to more-worked teas.

The four names

GB/T 22291-2017 sets four products, separated by how much leaf accompanies the bud and which cultivars are permitted.

Silver needle is buds alone, from the large-leaf da bai or the narcissus shuixian cultivars. White peony adds one or two leaves to the bud. Gong mei is pinned to the qunti (群体种), the heirloom seed-grown population cultivars, and to those only. Shou mei is leafier still. Each product carries an official physical reference sample (shiwu biaozhunyang 实物标准样) against which a batch is judged.

What "white" names

White tea takes its name from the down. The unopened bud is covered in fine trichomes, called in Chinese bai hao 白毫, "white hair," and these give the dry leaf its silvered, whitish cast. On silver needle, made only from buds, the down lies thickest and unrubbed, because nothing in the process rolls or works it off.

The colour named is the dry leaf's, not the liquor's. Brewed white tea pours pale yellow to gold.

What white tea is not

It is not uncaffeinated, and not reliably the lowest-caffeine tea. A peer-reviewed measurement of brewed white, green, and black teas found caffeine ranging from 14 to 61 mg per serving with no observable trend by type (Chin et al.³, Journal of Analytical Toxicology, 2008). Silver needle, being all buds, can carry relatively high caffeine, because buds are caffeine-rich.

It is not any pale tea. White tea is a processing class, defined by the standard through the wither-and-dry, not a color category. A pale liquor does not make a tea a white tea.

The standard that defines it

Two national standards govern the subject. GB/T 22291-2017, "White tea," issued 1 November 2017, replaced the 2008 version and sets the definition, the four products, the permitted cultivars, and the water-soluble-extract requirement. GB/T 31751-2015² governs compressed white tea (jinya baicha 紧压白茶), the cakes and bricks pressed from finished white tea by steaming and shaping.

White tea's home ground is Fujian. Fuding, on the coast, has a maritime climate; Zhenghe, inland, is mountainous and forested; each has its own da bai cultivars. Fuding White Tea was recognized as a protected geographical indication in 2009 (AQSIQ Announcement No.32 of 2009⁶).

GB/T 22291-2017 makes the term specific: the permitted cultivars, withered, dried, sorted, and judged against a physical reference sample.