Frequently Asked Questions


What is the caffeine content in tea vs. coffee?

The caffeine content for an average cup of green tea is usually stated at around 15 - 20 mg. per 8 oz. cup. Coffee, by comparison, can range from 100 - 140 mg per 8 oz. cup, depending on the method of brewing used. Caffeine content in highly oxidized teas, like very dark oolongs and black tea, can range up to 50 mg of caffeine per 8 oz. cup, almost half that of coffee. In our experience, the greener and fresher the tea, the lower the caffeine effect, this is attributed in part to the higher concentration of theanine found in the fresher green and white teas.


What is tea?

Camellia sinensis is the scientific name of the plant species whose leaves and leaf buds are used to produce tea. White tea, green tea, oolong and black tea are all harvested from this species, but are processed differently to attain different levels of oxidation.  Only tea that comes from this species of plant is considered a “true tea” any other type of herbal infusion with hot water is called a “tisane”


The name sinensis is the Latin word for "Chinese”.  Some other names for the tea plant include Thea bohea, Thea sinensis and Thea viridis.


Where does tea grow?

Camellia sinensis is native to mainland South and Southeast Asia, but is today cultivated across the world, in tropical and subtropical regions. It is an evergreen shrub or small tree that is usually trimmed to below two metres (six feet) when cultivated for its leaves.  The flowers are yellow-white, 2.5–4 cm in diameter, with 7 to 8 petals.


What part of the tea plant is used for making tea?

Tea leaves are generally used for producing tea and are 4–15 cm long and 2–5 cm broad. Fresh leaves contain about 4% caffeine.  Different aged leaves produce differing tea qualities, since their chemical compositions are different. Usually, the tip (bud) and the first two to three leaves are harvested for processing. This harvesting is repeated every one to two weeks.


What is the chemical composition of tea?

Tea contains many forms of poly-phenols, which include flavanols, flavandiols, flavonoids, and phenolic acids; which can account for up to 30% of the dry weight of tea. Most of the green tea poly-phenols are flavonols, commonly known as catechins.


Catechins are highest in concentration in white and green teas while black tea has substantially less due to its oxidative preparation. Caffeine, theobromine, and theophylline, are the principal alkaloids found in tea and account for about 4% of its dry weight. In addition, there are phenolic acids such as gallic acids, and characteristic amino acids such as theanine.  In addition black or red teas, through the process of oxidation become higher in theaflavins and thearubigins with these making up about 10-20% of the dry weight of black/red tea.


What are catechins?

Catechins are bioflavonoids, polyphenols and powerful anti-oxidants. The best source of catechins is white tea, with green tea coming a close second. Catechins are linked to evidence of fighting tumors as well as enhancing immune system function, due to their polyphenol antioxidant character, which is well established in scavenging reactive oxygen species.


What is theophylline?

Theophylline is a methylxanthine drug used in therapy for respiratory diseases such as COPD or asthma under a variety of brand names. As a member of the xanthine family, it bears structural and pharmacological similarity to caffeine. It is naturally found in black tea and green tea.


What is theobromine?

Theobromine is a stimulant frequently confused with caffeine. Theobromine has very different effects on the human body from caffeine; it is a mild, lasting stimulant with a mood improving effect, whereas caffeine has a strong, immediate effect and increases awareness.


What is theanine?

Theanine is an amino acid commonly found in tea.  Studies have shown that theanine is able to cross the blood-brain barrier, and can have psychoactive properties.  Theanine has been shown to reduce mental and physical stress and improves cognition and mood in a synergistic manner with caffeine.


What are theaflavins?

Theaflavins are antioxidant polyphenols that occur in tea leaves during the oxidation (or fermentation) of tea leaves, such as in black tea. Theaflavins are types of thearubigins, and are therefore reddish in color.


What are thearubigens?

Thearubigins are polymeric polyphenols that are formed during the oxidation (or fermentation) of tea leaves and are reddish in color.  Thearubigins have been shown in recent studies to have some antioxidant properties as well.  


Do different teas have different chemical properties?

Yes, the leaves of Camellia sinensis, if not dried quickly after picking, soon begin to wilt and oxidize. This process resembles the malting of barley, in that starch is converted into sugars; the leaves turn progressively darker, as chlorophyll breaks down and tannins are released.

This is why it is generally accepted that the greener and fresher the tea, the more antioxidant compounds, such as catechins, it contains. More oxidized teas contain fewer antioxidants, and more compounds such as theaflavins and thearubigins which have their own unique antioxidant properties.  Although antioxidant content can vary dramatically from tea to tea so it can be difficult to generalize.  While all tea contains tannins, using fresh, whole leaf tea, and preparing it properly (such as using Gong Fu or Gai Wan style) can reduce the number of tannins released into your cup.


How many different varieties of tea are there?

There are many different varieties of tea, the most common of which are listed below:


White tea

Young leaves (new growth buds) that have undergone no oxidation; the buds may be shielded from sunlight to prevent formation of chlorophyll. White tea is produced in lesser quantities than most of the other styles, and can be correspondingly more expensive than tea from the same plant processed by other methods. It is also less well-known in countries outside of China, though this is changing with the introduction of white tea in bagged form.


Green tea

The oxidation process is stopped after a minimal amount of oxidation by application of heat; either with steam, a traditional Japanese method; or by dry cooking in hot pans, the traditional Chinese method. Tea leaves may be left to dry as separate leaves or rolled into small pellets to make gun-powder tea. The latter process is time-consuming and is typically done only with pekoes of higher quality. The tea is processed within one to two days of harvesting.



Oxidation is stopped somewhere between the standards for green tea and black tea. The oxidation process will take two to three days. Along with Pu-erh, oolong is the tea most frequently prepared with the traditional gong fu style. Green oolongs tend to have very grassy, crisp characteristics, while dark oolongs tend to be smoother and somewhat sweeter. Oolongs in between the two (ban sheng ban shou; half fresh half dark) can carry the characteristics of either, depending on the level of oxidation.


Black tea/Red tea

The tea leaves are allowed to completely oxidize. Black tea is the most common form of tea in southern Asia (India, Sri Lanka, Bangladesh, Pakistan etc) and in the last century many African countries including Kenya, Burundi, Rwanda, Malawi and Zimbabwe. The literal translation of the Chinese word is red tea, which may be used by some tea-lovers. The Chinese call it red tea because the actual tea liquid is red. Westerners call it black tea because the tea leaves used to brew it are usually black. However, red tea may also refer to rooibos, an increasingly popular South African tisane. The oxidation process will take around two weeks and up to one month. Black tea is further classified as either orthodox or CTC (Crush, Tear, Curl, a production method developed about 1932). Unblended black teas are also identified by the estate they come from, their year and the flush (first, second or autumn). Orthodox and CTC teas are further graded according to the post-production leaf quality by the Orange Pekoe system.


Pu-erh (Pu'er; Pu Er)

(also known as Póu léi (Polee) in Cantonese), Two forms of pu-erh teas are available, "raw" and "cooked". "Raw" or "green" pu-erh may be consumed young or aged to further mature. During the aging process, the tea undergoes a second, microbial fermentation. "Cooked" pu-erh is made from green pu-erh leaf that has been artificially oxidized to approximate the flavour of the natural aging process. This is done through a controlled process similar to composting, where both the moisture and temperature of the tea are carefully monitored. Both types of pu-erh tea are usually compressed into various shapes including bricks, discs, bowls, or mushrooms. Compression starts the second oxidation/fermentation process, as only compressed forms of pu-erh will age. While most teas are consumed within a year of production, pu-erh can be aged for many years to improve its flavor, up to 30 to 50 years for raw pu-erh and 10 to 15 years for cooked pu-erh, although experts and afficionados disagree about what the optimal age is to stop the aging process. Most often, pu-erh is steeped for up to five minutes in boiling water. Additionally, Some Tibetans use pu-erh as a caloric food, boiled with yak butter, sugar and salt to make yak butter tea. Teas that undergo a second oxidation, such as pu-erh and liu bao, are collectively referred to as black tea in Chinese. This is not to be confused with the English term Black tea, which is known in Chinese as "red tea".


Yellow tea

Either used as a name of high-quality tea served at the Imperial court, or of special tea processed similarly to green tea, but with a slower drying phase.


Flower Tea

Teas processed or brewed with flowers; typically, each flower goes with a specific category of tea, such as green or red tea. The most famous flower tea is jasmine tea, a green or oolong tea scented (or brewed) with jasmine flowers. Rose, lotus, lychee, and chrysanthemum are also popular flowers.


How do you store/preserve tea?

Here at The Whole Leaf we generally keep our teas in special freezers devoted exclusively to our tea. If a bag is sealed (un-opened or heat-sealed), you can place it directly into the freezer, and your tea will keep its flavor and freshness perfectly for 6 to 12 months. Most teas can be kept in the freezer up to 3 years with slight degradation in quality provided there is no fluctuation in temperature, and the bag is perfectly sealed.


If you have already opened your tea, and will be drinking it on a regular to semi-regular basis you can simply keep your tea stored in a cupboard in its resealable pouch.  This pouch when used properly and when the tea is kept in a cool, dark place with minimal exposure to air will keep your tea fresh for 4-6 months.


Where does our tea come from?

We import the majority of our teas directly from family owned farms throughout China and Taiwan.  We seek to source only teas grown in accordance with time-honored traditions and utilizing the most natural growing methods.  Most ofl the teas we source are either certified organic in accordance with USDA standards or certified organic under Taiwanese standards, which to date have not been accredited by the USDA.


Our green teas are from Anhui and Zhejiang province.  Our white teas and high mountain oolong are from Fujian and our unrolled dark oolongs come from Wuyi Mountain. Our best rolled oolongs come from the Nantou region of Taiwan. Our Pu'er is from Yunnan province.


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