If this is coffee, please bring me some tea; if this is tea, please bring me some coffee. Abraham Lincoln

　　Every cup of coffee you drink owes its existence to a fruit that grew wild in the Yemeni desert. The Sufi mystics of Yemen were the first to roast and brew the seeds into a drink. It helped them stay awake during long hours of prayer. It spread to Ethiopia (where it was banned by the Ethiopian church) and then to the Arab world. Coffee houses called kaveh kanes (from where we get "coffee" and "café") sprang up on every corner. By the 15th century, Mecca was filled with men with mugs.

　　The habit spread to the rest of Europe in the 17th century. One of the first coffee houses in England was opened in Oxford by Jacob, a Turkish Jew, in 1650. Its coffee was described as "a simple Innocent thing, incomparable good for those that are troubled with melancholy".

　　Coffee became popular with scholars as it sharpened the mind rather than dulled it like alcohol. Coffee houses became meeting places, debating chambers and even laboratories. Isaac Newton and Edmond Halley once dissected a dolphin on the table of a coffee house in London. Lloyd's of London and the Stock Exchange started life as coffee houses. But the craze had its detractors. The brewing of ale had long been the preserve of women, known as "brewsters" or "alewives". In 1674, a group of them – alarmed at falling trade in taverns – drew up the Women's Petition Against Coffee, claiming: "Coffee makes a man barren as the desert out of which this unlucky berry has been imported."

　　For centuries, Arabia controlled the coffee industry until (as legend has it) a pilgrim from Mecca smuggled beans back to India and began an agricultural revolution. The Dutch also managed to get a plant back to Amsterdam and to their colonies in Indonesia, so Europe soon had new cheaper sources for their beans. Coffee is now grown in more than 70 countries and is the second most commonly traded commodity in the world after oil.

　　The most expensive coffee in the world comes from the droppings of the Asian palm civet, a small catlike animal that loves to eat coffee cherries. The cherries only partially digest and the seeds are excreted intact. The droppings are washed and the beans, sold as Kopi Luwak, can cost hundreds of dollars per pound. The partial digestion process is supposed to add a wonderful musky flavour.

　　Coffee does not make you alert. If you are a regular drinker of coffee, drinking it just eases the symptoms of caffeine withdrawal. So, if you never drink coffee you're probably more alert than a regular drinker who has just knocked back a double espresso. The effects of caffeine usually last between two and three hours, although that can extend to four or five hours depending upon an individual's sensitivity and metabolism.

　　A cup of filter coffee contains about three times as much caffeine as a cup of tea, although dry tea leaves do contain a higher proportion of caffeine by weight than coffee beans. The higher the temperature of the water, the greater the caffeine extracted from beans or leaves. An average 30ml espresso contains about the same amount of caffeine as a 150ml cup of PG Tips. So a single-shot cappuccino or latte won't give you much more of a caffeine hit than a cuppa. A cup of instant coffee, on the other hand, contains only around half the caffeine of a filter coffee.

　　Stronger than tea?

　　Does it wake you up?

　　Coffee houses

　　Desert fruit