Compression

What it is

Finished leaf is briefly steamed to make it pliable, packed into a cloth bag or mould, and pressed under stone or hydraulic force before being dried slowly. The practice began as a transport solution: compressed tea survives long overland journeys that would reduce loose leaf to dust. Its modern purpose is different. A pressed cake has far less surface exposed to air than the same weight of loose leaf, so it changes more slowly and more evenly in storage, which is precisely what long-term ageing needs. Compression is now applied to white tea as often as to dark tea for exactly that reason.

Also transliterated as: jin ya, jinya.

What it does to the leaf

Reduces the leaf’s exposed surface area and fixes it in a stable physical form, slowing and evening out subsequent change.

What it does to the cup

Little immediate effect beyond a slight steaming note; the consequence is over years, where pressed tea matures more evenly than loose leaf.

Variants that matter

Ways this step is carried out that produce genuinely different results, rather than regional names for the same thing.

Bing cha (round cake)

The standard pu-erh format, conventionally around 357 g, stacked in sevens for transport.

Tuo cha (nest)

A bowl or nest shape in sizes from a few grams to several hundred; the small ones are single-serving.

Zhuan cha (brick)

Flat rectangular bricks, the traditional border-trade format and the shape used for Fu Zhuan and Qing Zhuan.

Other steps at the Pressing stage

• Cake wrapping and tong packing — The paper, the bamboo shell and the stack are part of how the tea ages, not packaging around a finished object — and the wrapper is also the document.
• Log packing (Qian Liang) — Steamed dark tea rammed into a woven casing and compressed by rolling and treading the whole column, producing a tea shaped like a pillar rather than a cake.
• Pounding to a paste (mortar-beaten leaf) — Hot steamed leaf beaten in a mortar until it stops being separate leaves and becomes one mass, which is then formed by hand. The output of the step is a paste, not a shape.
• Steam softening before pressing (zheng ya) — Dry leaf is briefly steamed so it can be compressed without shattering — a few seconds too many and the cake has been part-cooked before it starts its life.
• Stone pressing — Forming a cake under a shaped stone weighted by a person standing on it, which gives a looser cake than a hydraulic press does.

Teas that go through this step

• Aged white tea cake
• Bingdao sheng pu-erh
• Bulang sheng pu-erh
• Cheongtaejeon
• Fu Zhuan
• Goishicha
• Hand-pressed Fu Zhuan
• Hei Zhuan
• Hua Juan Cha
• Hua Zhuan
• Jingmai sheng pu-erh
• Kang Zhuan
• Lao Ban Zhang sheng pu-erh
• Light-fermented shou pu-erh
• Menghai shou pu-erh
• Nannuo sheng pu-erh
• Pressed white tea cake
• Qian Liang Cha
• Qing Zhuan
• Sheng dragon ball
• Sheng pu-erh (raw)
• Shou pu-erh (ripe)
• Shou pu-erh brick
• Tuocha
• Xigui sheng pu-erh
• Yiwu sheng pu-erh
• Zhangping Shui Xian

Guides covering this step

• Tea trade routes — The routes tea travelled shaped the tea itself. Compression, fermentation and heavy oxidation are all, in part, answers to the question of how to move leaf a very long way without it turning to dust.
• Storing a cake, storing loose leaf, and breaking one up without wrecking it — Compression is a storage decision before it is a shipping one, and the wrapper is part of the store rather than packaging to be discarded. Breaking a cake badly is the most common way to make a good tea brew worse.
• Every compressed form was an answer to a specific problem — Cakes, bricks, nests and coins are not decorative and are not archaic survivals. Each shape encodes a transport distance, a counting method, a tax assessment or a storage regime, and reading them that way explains most of what a compressed tea is.