Black Tea

Black Tea 101

Black tea is believed to have originated from changes that happened to tea leaves during long-distance transportation. Under different temperature and humidity conditions, the fresh leaves underwent chemical changes, mainly the oxidation of tea polyphenols. As oxidation continued, many tea polyphenols were transformed, and new compounds, such as theaflavins and thearubigins, were formed. The aroma also changed, giving black tea its special reddish-brown color, sweet aroma, and rich, smooth taste.

Black tea is a fully oxidized tea. Its production mainly involves four steps: withering, rolling, oxidation, and drying. During withering, the leaves lose some water and become softer. Rolling breaks some of the leaf cells and helps release the tea juice, preparing the leaves for oxidation. Oxidation is a key step in developing the color, aroma, and taste of black tea. Finally, the leaves are dried to stop oxidation, develop the aroma, and reduce moisture, allowing the tea to be stored for a longer time.

Black tea gets its name from the dark color of its dry leaves. When brewed, the tea liquor and infused leaves often appear reddish, which is why it is called Hong Cha (红茶), meaning “red tea,” in Chinese. In Western countries, it is known as black tea, named after the dark appearance of the dry leaves.

This difference in naming reflects how Chinese and Western tea traditions describe the same tea: by the color of the brewed tea in China and by the color of the dry leaves in the West.

For the best results, brew Chinese black tea in a white porcelain gaiwan with a capacity of 110–130 ml. Porcelain does not absorb tea aromas, and a gaiwan allows you to pour the tea quickly and observe its color.

Use water at 90–95°C (194–203°F). After boiling, let the water cool for 1–2 minutes before brewing. A good starting point for the tea-to-water ratio is 1:50. For 150 ml of water, use about 3–5 g of loose-leaf tea, adjusting the amount to your taste. Keep the first few infusions short to prevent excessive bitterness and astringency. High-quality Chinese black tea can often be steeped 5–8 times, with each infusion revealing different aromas and flavors.

Tip: Pour out all the tea after each infusion. Leaving tea liquor in the gaiwan can make the next infusion too strong or bitter. Adjust the water temperature, tea quantity, and steeping time to suit the specific black tea you are brewing.

Although black tea is traditionally called “fully fermented tea”, the process is more accurately described as oxidation rather than true fermentation.

Fermentation usually involves microorganisms such as yeast or bacteria breaking down organic substances, often producing alcohol, acids, or other compounds. In black tea production, however, the main process is enzymatic oxidation. Enzymes in the tea leaves help catechins react with oxygen in the air, forming compounds such as theaflavins and thearubigins. These compounds contribute to black tea’s dark color, rich aroma, and distinctive flavor.

A familiar example is a sliced apple turning brown when exposed to air. A similar type of oxidation occurs in tea leaves, where polyphenols react with oxygen and form colored compounds. The term “fermentation” became widely used in tea processing because the leaves change color and develop new aromas during this stage.