What is Black Tea?

Pouring black tea into a flowered tea cup with a pile of black tea leaves

The Origins of Black Tea

Black tea is a delicious, robust tea with warm flavors and an often distinct astringency. It is delicious plain, with a dollop of milk, or sweetened with honey. We drink bracing black teas to warm up on cold winter days, sweet iced black teas to cool down in the summer, and weakly brewed teas with lots of honey for sore throats. For these and many other reasons, black tea is the tea we are most familiar with in the West. But interestingly, black tea is a relative late comer to the tea world and did not exist as we know it today before the 17th century. 

Prior to the invention / discovery of black tea, most Chinese people consumed primarily green teas and oolongs. In the 17th century, however, Europe began importing tea and a whole new market opened up - but this new market was not without its challenges. It is thought that the Chinese started experimenting with oxidation and fermentation to prolong the shelf-life of teas that now had to make very long ocean or overland voyages to an increasingly voracious foreign market in Europe. And, thus, black tea was born!

Today, black tea is produced in many different countries, including China, Japan, Taiwan, India, Sri Lanka, Kenya, Rwanda, and more!

How is Black Tea Made?

If you started reading this article thinking that there is a black tea plant and a green tea plant, you are not alone! This is a common misconception in parts of the world where the tea plant (camellia sinensis) doesn't grow natively - like here in the United States! It is natural to assume that two beverages with such wildly different colors and flavor profiles must come from different plants. In practice, however, how the leaves are processed changes their appearance, flavor, and even chemical composition, creating the beautiful white, green, oolong, black, and pu erh teas we enjoy so much.

The Process for Making Black Tea

1. Plucking

Most black teas are made from mature camellia sinensis leaves and may be plucked either by hand or by machine. Special black teas like golden bud teas and teas known as “beautiful teas” are carefully plucked by hand to ensure composition and quality. 

2. Withering

Chinese Black Teas

During the withering phase, leaves are withered either naturally or mechanically. In natural withering the leaves are spread on the ground or bamboo racks for 5 to 6 hours with frequent stirring. Mechanized withering takes about 4 hours and uses sieves over brick containers that are heated using hot air circulated from wood fires (this gives Chinese black tea its characteristic smoky flavor). Withering removes about 60% of the moisture from the leaves and allows the leaves to soften, preparing them for rolling.

Indian Black Teas

In India, producers reduce the water content of leaves by spreading the freshly picked leaves out in withering vats. The leaves are spread on grids of metal, jute, or plastic that allow air to circulate. The humidity and temperature are constantly monitored during withering, and after 14-17 hours the moisture content of the leaves will be reduced by 60-70%. 

3. Rolling

Once the leaves are withered and softened, they are rolled by hand or by machine to break down the structure of the cells, triggering enzymatic oxidation. 

4. Oxidation

Black tea is fully oxidized, giving the leaves their characteristic dark hue that brews to a beautiful, deep-reddish-brown liquor. How your black tea is oxidized depends on the traditions of the production region and tea estate. 

Oxidation is the defining step of black tea production, and it all comes down to some pretty interesting chemistry. During oxidation, the originally colorless polyphenols in camellia sinensis leaves are transformed into theaflavins and thearubigins. It is this breakdown that gives black tea its color and astringency - and also leads to the interesting way your body processes the caffeine in different teas (hint: black tea might not be as caffeinated compared to green tea as you think!)

If your oxidation period lasts too long, the tea will develop a thick liquor and a strong, almost fermented taste. Too little oxidation results in a thin liquor and a green or raw infusion. 

Chinese Black Teas

Dependent on the conditions of the day and location, the oxidation process for black teas may last 8-12 hours. During oxidation, the leaves are spread out and covered with wet cloths to further stimulate the enzymatic oxidation reaction. The ambient temperature should be around 72°F. 

Indian Black Teas

Indian black teas are spread out on ceramic or steel trays in a humid environment between 68 and 86°F. For quicker oxidation, the leaves are spread in a thin layer. Alternatively, if the producer is looking for a slower oxidation, the layer will be relatively thick. In modern times, humidity may be controlled by a humidifier to maintain at least 90% humidity. Some first flush Darjeelings may only oxidize for 15-30 minutes! Many teas from Assam, in contrast, will oxidize for up to 4 hours. Either way, this is far less time than it takes to oxidize leaves using the traditional Chinese method. 

5. Drying

Oxidation is halted and residual moisture is removed using various techniques until the moisture content is down to 2-6%. Most methods in China involve blowing warm air through conveyer belts. Indian black teas are placed on conveyors or revolving trays in heated machines. 

6. Sorting & Sifting

At this point in the process, the tea leaves are sorted into different grades and undesirable elements like dust, branches and other residue are removed. In China, higher quality teas are usually hand sifted using a bamboo sieve. In India, the leaves are sorted using vibrating grids of varying sizes placed on top of each other. This keeps the larger leaves on top, intermediate leaves in the middle, and crushed leaves and dust at the bottom. (Fun Fact: In Darjeeling all teas are sorted this way and leaf size is used as an indicator of grade.)

7. Firing (Optional - Chinese Black Teas Only)

This last, optional stage of the process further reduces moisture content and aids batch standardization. 

Is There a Difference Between Chinese Black Teas and Indian Black Teas?

In an effort to reduce trade reliance on China, the British developed the tea industry in India in the late 19th century. Their focus in this development was as much if not more about efficiency than quality, and almost all Indian teas are processed mechanically. 

The key differences between Chinese black teas and Indian black teas is characteristic flavor. Most Chinese black teas will have a more mellow tannin and may have a slightly smokier flavor depending on how they are withered and fired. 

Most Indian black teas, on the other hand, have a more prominent and astringent tannin. If you are a fan of Breakfast Teas, you prefer the strong, robust flavors of an Indian black tea like Assam. Darjeeling is a bit more nuanced with particularly high quality tea estates producing extremely aromatic teas with notes of spice, fruit, and malt.

These differences in flavor are attributable to both terroir and production. Below we go over some of the key differences between how Chinese and Indian tea producers process black tea.

The Orthodox Method - India

Developed around 1860, the Orthodox Method uses a largely mechanized process and is used to produce the higher grade Indian teas. This process includes all the steps mentioned above: Plucking, Withering, Rolling, Oxidation, Drying, and Sorting.

The CTC Method - India

Developed in the 1930s, the Crush-Tear-Curl (CTC) method speeds up the oxidation process and increases the quantity and speed of harvest yields. Rather than the more complex Orthodox or Chinese methods for processing black teas, CTC consists only of a quick withering followed by cutting and crushing rather than rolling. The leaves are then further torn apart in a machine called a Rotorvane. Then the leaves are rolled into small beads in a large barrel. Usually the leaves used for CTC teas are of a coarser, inferior quality.

This method of course revolutionized the tea industry in much the same way that mechanization changed the world during the Industrial Revolution. Similarly, this revolution in efficiency was at the expense of quality in favor of efficiency, volume, and uniformity. 

Camellia Sinensis Sinensis vs. Camellia Sinensis Assamica

Most black teas are made from the tea plant camellia sinensis var. assamica. Assamica is native to both India and the Yunnan Province in China, and it was the discovery of assamica in India that allowed the British to establish the tea trade in that country. Camellia sinensis var. sinensis, with sinensis referring to China, literally means Chinese tea plant. Today, there are many different cultivars from both var. sinensis and var. assamica grown to produce teas and you will find both varietals in multiple regions. That said, it is safe to assume that if you are drinking a black tea it is likely var. assamica, even if it's not from the Assam region in India!

How is Black Tea Different from Green Tea?

Black tea and green tea differ in one major area: oxidation. In green teas, the natural enzymatic oxidation is halted after withering using either steaming (Japan) or panning (China). This additional step of heating the leaves until the enzymes that cause oxidation lose their potency is essential in keeping green teas, well, green!

What is the Best Black Tea? (Black Tea Grades)

As with many things, what you think is the best black tea will be subjective and based on your own tastes. With that said, black tea grades are not necessarily an indication of quality, though it is true that most whole leaf teas will be of better quality than crushed. This is because whole leaf teas brew a more nuanced and aromatic infusion while broken and crushed leaves result in a darker liquor with a flatter flavor profile. 

The three major tea grades are: whole, broken, and crushed, referring to the state of the leaves. 

If you’re looking for a way to differentiate your whole leaf teas, in China the quality of tea is usually indicated by growing region and producer. You will find that terroir (the character soil conditions impart to a tea) is an excellent way to determine whether or not you will like a particular tea. Both Yunnan and Fujian Provinces are renowned for their black teas and are an excellent place to start your explorations!

In India, the British and Dutch traders established a complex grading system based on the size and quality of the leaves. 

Some key grading vocabulary:

  • Tippy - the presence of flowering buds
  • Golden - the tips (buds) that turn golden after oxidation
  • Flowery - the floral aroma released by buds
  • Orange - a historical reference to the first European importers of tea: the Holland-Nassau Dutch royal family 
  • Pekoe - meaning “white down,” pekoe comes from pak-ho and refers to the final bud on the branch typically covered in a fine, white down.
  • Quality Indicators: Special, Finest, 1

The producers will use the first initials of these grading terms to indicate the quality of the tea. Sometimes they will add Special, Finest, or the numeral 1 to indicate exceptional batches. 

Our Ceylon Orange Pekoe, therefore, is not an orange flavored black tea, but a whole leaf black tea with buds from Sri Lanka (colonial name: Ceylon)!

How Do You Prepare Black Tea?

While there is definitely room for nuance in the preparation of black teas (for example, some First Flush Darjeelings may benefit from a shorter steep and cooler water), most black teas may be brewed for 3 minutes with water that’s just under boiling at 205°F.  

We recommend 5 grams of tea to 16oz of hot water (this is our standard to-go size at our tea bar). Most mugs at home will hold about 6-8oz of liquid and use 2-3g of tea. Don’t forget whole leaf teas may be re-steeped several times in the Western method at increasing time intervals. 

For traditional brewing, you will fill your Gaiwan or Yixing about 1/3 full and brew at 205°F for about 45 seconds to 1 minute. Full leaf black teas brewed in this manner will steep 5-6 times at decreasing time intervals as the leaves open more fully. 

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Sources: 

Gascoyne, K., Marchand François, Desharnais, J., & Américi Hugo. (2016). Tea: History, terroirs, varieties. Firefly Books. Ltd.