What is Caffeine?

We hear a lot about caffeine content of drinks and how bad it is for us but what is it?

The Science Bit

Caffeine is a naturally occurring stimulant called trimethylxanthine, chemical formula C8H10N4O2. In its pure form it is a white crystalline powder that tastes bitter. It was first isolated as pure caffeine in 1819 by a German Chemist called Friedlieb Ferdinand Runge, and Emil Fischer derived the structural formula of the compound in 1897 (Fischer was awarded the Nobel Prize in 1902, his work on caffeine was part of the work that won the award).

In Your Body

Scientists measure drugs by their “half-life”; this is the time it takes the body to break down half of the dose. In the case of caffeine the “half-life” varies dramatically from one person to another and can be anything from 3 hours to 12 hours depending on age, general health, metabolic rate and weight. On average caffeine is absorbed by the small intestine within 45 minutes of ingestion and then distributed throughout all the tissues of your body, the central nervous system is stimulated and peak blood concentration is reached within an hour. Everyone will react differently to this and to different degrees but the common affects are to ward off drowsiness, reduce physical fatigue and increase alertness.


History of Caffeine & Humans

Have you had your coffee yet today? Many of us have a love-hate relationship with caffeine; we love the taste and effects of a really good cup of coffee but hate the way we feel if we don’t have it or if we have too much of it. This is the first in a series of articles exploring our relationship with caffeine beginning with the history of caffeine and humans. We commonly consume caffeine by infusions extracted from the seed of the coffee plant or leaves of a tea bush and through products derived from cocoa beans and kola nuts.


The first recorded consumption of caffeine is reputed to be Emperor Shen Nung in around 2700 BC who drank a hot drink brewed from leaves of a tea bush. Whether this is true or not, tea drinking was certainly established in China many centuries before the West; tea containers have been found in tombs dating from the Han Dynasty (206 – 220 AD) and in the late eighth century the first book was written entirely about tea. Tea was introduced to Europe at the end of the sixteenth century and in 1606 the Dutch imported the first commercial consignment of tea from China. From Holland it spread through Europe, where it was fondly adopted in Britain and Ireland, and across to America.


Legend has it that Ethiopian Nomads discovered coffee through observing that when their goats ate the fruit of the coffee plant they would have an energy boost, they then ate some and found they too had a boost of energy. Legend aside, coffee beans come from Ethiopia and the first reliable record of coffee drinking is in the Sufi monasteries in the Yemen in the mid fifteenth century. It is then traced as spreading across Egypt and North Africa and into the Middle East, Turkey and Persia by the sixteenth century, the first coffee house opened in Istanbul in 1554. An early writer on coffee noted in 1587 that one Sheikh said of coffee “it drove away fatigue and lethargy, and brought to the body a certain sprightliness and vigour”. Coffee drinking then moved into Italy, with the first European coffee house opening in Venice in 1645, and the rest of Europe followed.


Cocoa originates in South America and was first used by the Mayans to create a beverage with water, vanilla, black pepper and spices. The cocoa beans were also used as currency by South American civilisations and only consumed as they wore out, apparently you could buy a horse for ten beans. The Spanish introduced cocoa to Europe in the mid seventeenth century and from there it has spread around the globe.


Kola nuts are native to the tropical rainforests of Africa, the tree it comes from is related to cocoa. Kola nuts are chewed by West African cultures to ease hunger pangs and restore vitality. In the 1800s a pharmicist in Georgia took extracts of a Kola nut, sugar, carbonated water and other ingredients to produce the world’s first cola drink “Coca-Cola”. Since then Kola has been the source of caffeine in many soft drinks.