Cloth Bags and Stone Molds: The Details of Hand-Pressing

If you visit a tea mountain or factory in Yunnan, the most fascinating stop is watching cakes being pressed by hand: steam rising from the steamers, cloth bags flying, a stone mold being twisted back and forth underfoot. The little dimple on the back of a tea cake is formed in those few minutes.

The Hand-Pressing Process

1. Weighing: the portion for one cake is weighed to spec, for example 357 grams. Careful makers put in the face tea first, then the inner tea.
2. Steaming: the tea goes into a steaming cup with holes in the bottom, set over boiling water for about 30 seconds to 1 minute, until the leaves are soft and tacky.
3. Bagging: the steamed tea is poured into a cloth bag, opening facing up.
4. Kneading: the maker grips the opening, twisting and tightening it while rolling and pressing the bag on the table, shaping the tea into a flat, round ball.
5. Adding the neifei: the neifei (the small ticket pressed into the cake) is usually placed on the tea while bagging or kneading and pressed in along with it.
6. Stone pressing: the kneaded ball is set on a platform with a stone mold on top, and the maker stands on the mold and twists side to side to press it.
7. Setting: the cake rests, still in its bag, for anywhere from a few minutes to over ten minutes until it cools and holds its shape.
8. Unbagging: the bag is untied, and the cake is taken out and sent to dry.

What the Cloth Bag Does

The cloth bag is the key tool of hand-pressing, usually sewn from cotton cloth or gauze:

• Holding the leaves: steamed tea is loose, and the bag gathers it into a ball so it doesn't scatter during pressing.
• Shaping: the twisting and tightening during kneading determine how round, thick, or thin the cake will be.
• Breathing: the weave lets steam and moisture escape, so the pressed cake is less likely to stay damp.

The bags need regular washing and drying, and they discolor with use. Old masters like to say you can tell how much tea a workshop has made by the color of its bags.

Where the Dimple on the Back Comes From

While kneading, the maker twists the bag opening into a knot, which ends up pressed against the center of the back of the ball. When the stone mold comes down, the knot pushes into the leaves and leaves a dimple on the back of the cake, sometimes called the "cake nest."

The dimple has practical benefits: the center of the cake isn't too thick, so moisture escapes easily during drying, and it gives you a good place to start when prying tea off. Machine-pressed "iron cakes" don't use cloth bags, so their backs are flat with no dimple. See Iron Cakes: Tightly Pressed Cakes Without a Dimple.

What Is a Stone Mold?

A stone mold is a cylindrical or square block of stone with a flat base, often with a handle carved into the top or sides. Weights vary by region, and it takes some effort for one person to move one. During pressing, the stone's weight plus the maker's body weight, combined with twisting side to side, flattens and compacts the tea.

Stone-pressed cakes receive gentler pressure than machine-pressed ones. They're moderately compressed and easy to pry apart along their layers. Some molds have patterns or characters carved into the base, which leave an imprint on the cake's surface.

How Long Does One Cake Take?

A skilled maker takes about a few minutes per cake, from weighing and steaming through kneading and twisting under the stone. After that, the cake still needs time to set in its bag. One person can only press a limited number of cakes a day, which is one reason hand-pressed stone-mold tea costs more than machine-pressed tea.

Why Hand-Pressed Cakes Aren't Perfectly Round

• Kneading pressure: every kneading is a little different, so the roundness and thickness of the ball vary.
• Direction of twisting: with a person twisting on top of the stone, the pressure can never be perfectly even, so edges are often thicker on one side than the other.
• Leaf maturity: tender tea is stickier and presses into neat rounds; coarser tea is less sticky, and its edges tend to be loose.

That's why stone-mold cakes often have rounded, slightly uneven edges and may even be a bit oval. That's not a flaw. It's the mark of handwork. Machine-pressed cakes have sharp edges and even thickness. For telling them apart by appearance, see Pressing Pu'er: Steaming, Stone Molds, Machine Presses, and Compression.

Hand-Pressed or Machine-Pressed?

Stone-mold cakes are moderately compressed, easy to pry apart, and change at a moderate pace in storage. Machine-pressed cakes are tight, uniform, and change more slowly. People who love the warmth of handwork tend to prefer stone molds, and those who value consistency tend to prefer machine pressing. Both are sensible choices.

Face Tea and Inner Tea

Careful hand-pressers add the tea in two portions when weighing: first the "face tea," with handsome leaves and plenty of buds, then the fuller-tasting "inner tea," with a final sprinkle of face tea on top. During kneading, the face tea ends up on the outside, so the finished cake shows attractive buds and leaves on its surface, while the inside, once pried open, is a bit sturdier. This "sa mian" technique lets one cake deliver both good looks and good taste.

FAQ

What is the cloth bag for? It holds the steamed tea, lets it be kneaded into a ball and shaped, and its weave lets steam escape.

How is the dimple on the back of a cake formed? The knot formed by twisting the bag opening sits against the back of the cake, and pressing under the stone leaves a dimple.

How long does it take to stone-press one cake? A skilled maker takes a few minutes from weighing to the stone, and then the cake needs time to set.

Why aren't hand-pressed cakes round? Kneading and twisting pressure differ each time, and leaf maturity affects stickiness, so shape and thickness vary.