Taste, colour and mouthfeel depend on the interaction between the two main components of tea, polyphenols and caffeine. Each component is astringent on its own, but as a complex the astringent character is reduced.

Water is known to contain gases absorbed from the air. Carbon dioxide (CO2) gas that is present in water effects the acidity.

Acidity of water plays a critical roll in the ionization of tea polyphenols and it contributes to the stability of the above complex.

CO2 in water is gradually released during the boiling process. Re-boiling will in fact further reduce CO 2 levels, resulting in a decrease in the acidity. As mentioned above this will effect the caffeine and polyphenol complexion, and bring about changes in the colour as well as the character of the brew.

Twice boiled water will therefore affect the taste of a good tea and hence our request that only freshly boiled water is used for brewing Dilmah tea.

Questions surrounding caffeine intake and risk of miscarriage and health of the foetus continue to be raised by pregnant women.

A study published in the journal of American Medical Association found no evidence that moderate caffeine use increases the risk of spontaneous abortions, growth retention or account for other factors. Another seven-year epidemiological study on 1,500 women examined the effect of caffeine, during pregnancy as well as on subsequent child development.

Caffeine consumption equivalent to approximately 3 ½ to 5 cups of tea per day had no effect on birth weight, birth length and head circumference of the baby. A follow-up examinations at age's eight months, four and seven years also revealed no effect of caffeine consumption on the child's motor development or intelligence.

A number of factors influence the metabolism of caffeine and the individual's response to caffeine indigestion. These include pregnancy, age, sex, body weight, diet, exercise, and stress smoking and alcohol consumption.

Pregnancy hampers caffeine metabolism. For example, in non pregnant women the break-down of half of the caffeine takes an average of 2.5 - 4.5 hours, 7 hours during mid-pregnancy and 10.5 during the last few weeks of pregnancy. As caffeine retention is longer during pregnancy, women sensitive to caffeine may be affected. As a result a moderate consumption of approximately 3-4 cups a day, is recommended for women during pregnancy.

For teas to be labelled decaffeinated, the caffeine content should not exceed 0.4% by dry weight, which is equivalent to approximately 4 mg of caffeine per 170 ml serving.

The process of decaffeination extracts the caffeine in tea. The current commercially available methods for decaffeinating black tea are solvent based extraction using ethyl acetate or methylene chloride, and extraction using supercritical (solid) carbon dioxide. All three methods extract caffeine with minimum effect to the quality of tea.

Tannins or tannic acid are not present in tea. Tea polyphenols were formerly referred to as tannins or tannic acids due to the similarities in the chemical structure. This has left many misguided notions about the effect of tea upon the human digestive system. Chemists generally group compounds into 'families' on account of common features in the synthesis of the molecules. For example both strychnine and morphine are alkaloids and have common structural features but the action on the human body is different. Strychnine is a powerful stimulant and morphine a powerful hypnotic.

Vegetable tannins are a large chemical family and some of them are loosely called tannic acids. These compounds possess the property of hardening animal tissues and turning hide into leather. Tea polyphenols on the other hand are called catechins, theaflavins and thearubigens, and are responsible for many of the health benefits associated with tea. Such as anti-hypercholestemic action, anti-hyperglycemic action, fat reduction action, anti-hypertensive action, anti- cancer action and many other health promoting effects. Current scientific literature points to the fact that tea polyphenols are biochemically very different to tannins.

Tea composition varies with climate, season, horticultural practices and variety. Polyphenols are the most important component in tea, as they constitute approximately 36 percent of the dry weight of tea. Other components of fresh green leaf include caffeine, protein and amino acids, carbohydrates, lipids, vitamins and minerals.

Green and black tea have similar chemical make-up. The primary difference between the two types lies in the chemical changes that take place during their production. In black tea the plant Polyphenols are oxidized and this is prevented in the manufacture of green tea.

One of the most important groups of Polyphenols in tea is the catechins in green tea, theaflavins and thearubigens in black tea. A variety of physiological effects have been attributed to tea catechins which are currently best known for their antioxidant activities.

Black tea is all-natural (non flavoured) and contains no additives. It is virtually calorie-free (1 calorie per 100 ml) and sodium free and is therefore a suitable beverage for individuals on calorie-reduced or low sodium diet. Tea includes fluoride, traces of vitamins A, K, C, B carotene and B vitamins.

Average daily consumption of tea in the United Kingdom, 3.43 cups (650 ml), provides very few calories and only a small amount of fat, whilst contributing valuable minerals and vitamins to the diet. It provides:

Although concerns have been expressed about consumption of iron, existing research and dietary knowledge indicate that tea is not likely to cause health risk, in individuals consuming a typically Western diet.

Dietary iron exists in two forms, heme iron (derived from animal) and non-heme iron (found in plants). The body better absorbs heme iron than non-heme iron. Between 15-35 % of heme iron is absorbed, while 2-20% is absorbed of non-heme iron. Non-heme iron is generally modified by other dietary components.

Certain components in grain, fruit and vegetables as well as polyphenols in tea reduce the availability of iron to the body. However, studies have shown that tea only decreases iron absorption when it is consumed simultaneously with food containing non-heme iron. Tea drinking between meals has no effect on iron absorption.

Moreover the ability of tea polyphenols to decrease iron absorption is reduced by the presence of other dietary constituents particular ascorbic acid (known to increase absorption of non-heme iron) and milk.

Green tea and black tea have similar but not identical chemical components. Despite the differences in chemical composition, both contain antioxidants called polyphenols and latest research evidence suggests both have similar biological effects. Green tea contains antioxidant compounds known as catechise while black tea contains theaflavins and thearubigens, which are polymerised from catechins.

Green and black tea comes from Camellia sinensis. Green tea is steamed immediately after plucking and retains a lighter colour and flavour. Black tea is allowed to oxidise and is then dried, resulting in a darker leaf colour and a more flavour and aroma.

The diuretic can be attributed to the caffeine present in tea and coffee. Caffeine increases diuretic action on the kidneys, increasing urinary volume and sodium extraction as a result of a decrease in the tubular re-absorption of sodium and water. Coffee contains a higher content of caffeine compared to tea. Research has shown that a 170ml (6-oz) serving of tea contains, on average 34mg of caffeine in comparison to 99 mg of caffeine in 170 ml serving of brewed coffee.

As a result the diuretic effect of coffee is greater compared to tea.

Clouding in tea is a result of the colloidal precipitate that is formed. This is called 'tea cream'. Tea creaming takes place when black tea is cooled below 400 C. A weak complexion is formed between caffeine and polyphenols (theaflavins and thearubigins). The tendency to cream down varies from tea to tea. In black tea without milk complexation and subsequent precipitation that occurs is negligible due to just 4% of caffeine.

In tea with milk a similar association takes place between the milk protein casein and various polyphenols. Due to the availability of casein in milk tea the complexion is greater resulting in larger precipitation.

The water used to brew the tea significantly affects the colour and the taste of a cup of tea. Tea brewed in soft water or permanently hard water (which contains CaSO4) appears brighter than if it is brewed in temporary hard water (that contains Calcium bicarbonate CaCO3).

High pH water that contains bicarbonate makes the infusion look darker brown due to the greater ionisation of the tea polyphenols. While lower pH as in lemon tea the infusion turns yellow. As for taste some teas are more suited to softer water such as the orthodox manufactured Assam leaf, while high grown Ceylon and CTC manufactured teas are better with temporary hard water.

It is the result of the high molecular weight components which are formed due to the influence of calcium and bicarbonate ions at the liquid water interface. The scum can be removed in two ways

1. by filtering the calcium ions
2. by adding acids to covert bicarbonate ions to CO2

Very little scum is formed on a cup of very strong tea. As the acidic tea polyphenols themselves partly neutralise the bicarbonate ions. It also should be noted that less than one mg of scum is formed in a cup of tea and it is not known to be harmful to human health.

Boiling water for too long does dramatically affect the quality of tea. The desirable brisk taste of tea is created by the interaction of two of its main components, caffeine and polyphenols. Each component is harsh on its own but as a complex the compounds moderate each other. Acid levels of water affect the behaviour of these components.

Water contains minerals and gases absorbed from the earth bed and air. Carbon dioxide absorbed by air makes the water slightly acidic that influence the colour and taste. High temperature changes the acidity of water and the acidity is reduced by gradually driving out carbon-dioxide. Therefore re-boiled water might well brew tea of a different colour and strength and is unsuitable to brew a good cup of tea.

Herbal Infusions, fruit based tisanes and floral infusions are not tea. There are only three types of tea, black tea, green tea and Oolong tea. In many countries, notably the USA, these infusions are usurping the health and other benefits of tea falsely. We give below a brief introduction to the most popular herbal infusions. Dilmah offers a selection of three herbal infusions, clearly differentiated from Dilmah black and green teas.

Chamomile herbal infusions are derived from the plant Chamomillae romanae. It is a one-year plant, which reaches a height of approx. 55.cm. Chamomile contains 0.6% - 2.4% essential oils such as angeloyl, methacryl and flavenoids as the main constituents. The white flower heads are mechanically harvested and dried in chambers to manufacture the commercial product.

Chamomile was known for its health benefits for centuries and the ancient Egyptians dedicated it to their sun god, and used Chamomile in their aromatherapy. This legacy of Chamomile lives on. Studies have that it is beneficial for complaints such as indigestion, nervousness, depression and headaches.

In testing its Chamomile based product Kamillosan, the Chemiewerke Hamburg Pharmacy of West Germany found that it reduces gastric acid and helps prevent ulcers. It also promoted tissue regeneration after patients had operations on their intestinal tract and urinary system. Chamomile decreases histamine, implicated in ulcers and the skin swelling, puffy eyes and headaches brought about on by allergies. It is given to children for digestive and hyperactive problems.

The Greeks named Chamomiles "kamai melon" (ground apple) inspired by its distinct apple like fragrance and the Spanish called it Manzanilla or “little apple”.

Peppermint originated from the Mediterranean but is now cultivated globally in the Balkans, Northern Europe and the USA. It is characterized by its strong aroma. It is a perennial herb with a flat root system. It reaches normally a height of approx. 2-ft and is harvested shortly before blooming. Peppermint contains 0.5 4 % essential oil that includes Menthol and menthol esters.

Written evidence of old Egypt indicates that Mentha plants were cultivated and exploited for medical use 1,000 years before Christian era. It also shows that Mint plants have represented a valuable object of trade, and was even accepted as tithes to pay taxes due.

Studies have shown that peppermint tea brings about considerable increase in the production of bile due to the presence of flavonoids. Peppermint leaf or extracts prepared from it are included in many (ca. 50) prepared cholagogues and bile-duct remedies, e.g. Cholagogum Nattermann (capsules, drops), etc. gastrointestinal Remedies (ca 50), e.g. Gastricholan Iberogast Ventrodigest, etc.), liver remedies (more than 10), hypnotics/sedatives (more than 10), e.g. Nerventee Stada, Esberi-Nervin drops, etc., and laxatives.

Usually consists of 70% Hibiscus and 30 % Rosehip. Hibiscus (Hibisci flos) originated in Angola but is now cultivated throughout the tropics. It is an annual herbaceous plant with lobed leaves that grows to a height of 5 m. Flowers with a 5-lobed calyx and divided epicalyx. Hibiscus for infusions is manufactured form the dried calyxes harvested from the fruit of the species.

It is principally taken as a caffeine-free refreshing drink taken in large amounts because of the plant acids. The plant acids which are difficult to absorb act as a mild laxative.

Hibiscus has been extensively used in the African Folk medicine. The drug is ascribed, among other things, spasmolytic, antibacterial, cholagogic, diuretic and anthelmintic properties. Studies have shown aqueous extracts of hibiscus flowers relaxes the muscles of the uterus and to lower the blood pressure.

Rosehip is derived from the plant Rosae pseudofructus. It is a shrub that grows up to a height of 5 m with thorn branches with flowers close to 5 cm in diameter with five petals. The drug consists of the dried hypanthia from various species of the genus Rosa with the fruit enclosed in them. Rosehip is native to Europe, Western and Central Asia, and North Africa but now it is cultivated in Chile, Bulgaria, Romania, China and Hungary. It was used in folk medicine as a result of its diuretic and laxative action due to the pectin and the plant acid content. Due to its high content of vitamin C Rosehip are used as breakfast teas.