Compressed tea, called tea bricks, tea cakes or tea lumps, and tea nuggets according to the shape and size, are blocks of whole or finely ground black tea, green tea, or post-fermented tea leaves that have been packed in molds and pressed into block form. This was the most commonly produced and used form of tea in ancient China prior to the Ming Dynasty. Although tea bricks are less commonly produced in modern times, many post-fermented teas, such as pu-erh, are still commonly found in bricks, discs, and other pressed forms. Tea bricks can be made into beverages like tea or eaten as food, and were also used in the past as a form of currency.

In ancient China, compressed teas were usually made with thoroughly dried and ground tea leaves that were pressed into various bricks or other shapes, although partially dried and whole leaves were also used. Some tea bricks were also mixed with binding agents such as flour, blood, or manure to better preserve their form so they could withstand physical use as currency. Newly formed tea bricks were then left to cure, dry, and age prior to being sold or traded. Tea bricks were preferred in Asian trade prior to the 19th century, since they were more compact and less susceptible to physical damage than loose leaf tea. This was important during transportation over land by caravans on the Tea Horse Road.

Tea bricks are still currently manufactured for drinking, as in pu-erh teas, as well as for souvenirs and novelty items, though most compressed teas produced in modern times are usually made from whole leaves. The compressed tea can take various traditional forms, many of them still being produced. A dome-shaped nugget of 100 g (standard size) is simply called tuóchá (沱茶), which is translated several ways, sometimes as "bird's nest tea" or "bowl tea". A small dome-shaped nugget with a dimple underneath just enough to make one pot or cup of tea is called a xiǎo tuóchá (小沱茶; the first word meaning 'small') which usually weighs 3 g–5 g. A larger piece around 357 g, which may be a disc with a dimple, is called bǐngchá (饼茶, literally 'biscuit tea' or 'cake tea'). A large, flat, square brick is called fāngchá (方茶, literally 'square tea').

To produce a tea brick, ground or whole tea is first steamed, then placed into one of a number of types of press and compressed into a solid form. Such presses may leave an intended imprint on the tea, such as an artistic design or simply the pattern of the cloth with which the tea was pressed. Many powdered tea bricks are moistened with rice water in pressing to assure that the tea powder sticks together. The pressed blocks of tea are then left to dry in storage until a suitable degree of moisture has evaporated.

Although the Chinese regard it as an inferior product, [tea bricks are] greatly esteemed by the Tibetans for [their] powerful flavor, which harmonizes particularly well with that of the rancid yak's butter which they mix with their tea. Brick tea comprises not only what we call tea leaves, but also the coarser leaves and some of the twigs of the shrub, as well as the leaves and fruit of other plants and trees (the alder, for instance). This amalgam is steamed, weighed, and compressed into hard bricks, which are packed up in coarse matting in subunits of four. These rectangular parcels weigh between twenty-two and twenty-six pounds—the quality of the tea makes a slight difference to the weight—and are carried to Kangting by coolies.

The brick tea is packaged [in Kangting] either in the courtyard or in the street outside, and it is quite a complicated process. When the coolies bring it in from Ya'an, it has to be repacked before being consigned upcountry, for in a coolie's load the standard subunit is four bricks lashed together, and these would be the wrong shape for animal transport. So they are first cut in two, then put together in lots of three, leaving what they call a gam, which is half a yak's load. Tea which is going to be consumed reasonably soon is done up in a loose case of matting, but the gams, which are bound for remote destinations, perhaps even for Lhasa, are sewn up in yakhides.

— André Migot, Tibetan Marches

Due to their density and toughness tea bricks were consumed after they were broken into small pieces and boiled. Traditionally, in the Tang Dynasty, they were consumed being ground to a fine powder. The legacy of using tea bricks in powdered form can be seen in modern Japanese matcha tea powders as well as the pulverized tea leaves used in the lei cha (擂茶) eaten by the Hakka people and some people in Hunan province.