48 Fun Facts About Caffeine

Caffeine keeps you awake mainly by blocking the receptors of which sleep-promoting molecule?

Adenosine builds up in the brain the longer you stay awake and makes you drowsy; caffeine is shaped enough like it to sit in its receptors without switching them on.

In the legend of coffee's discovery, the Ethiopian herder Kaldi saw which animals turn frisky after eating the berries?

Goats: in one telling Kaldi took the berries to a nearby monastery, where the abbot brewed them into a drink to stay awake through the long evening prayers.

Which composer wrote a comic 'Coffee Cantata' about a daughter who refuses to give up her coffee habit?

Johann Sebastian Bach wrote it in the 1730s, when he led the ensemble at a Leipzig coffee house; the daughter yields when her father threatens she will get no husband, then secretly spreads word that any suitor must let her drink coffee.

Which South African herbal tea is naturally caffeine-free?

Rooibos comes from a South African shrub in the pea family, not from the tea plant, so its leaves hold no caffeine at all.

Why do plants such as coffee and tea make caffeine in the first place?

As a natural pesticide against insects: at the doses found in the plants it puts bugs off feeding and can kill them, a defence so useful that coffee and tea evolved it separately.

Caffeine has been found to enhance the reward memory of which animals, encouraging them to return to a plant?

Honey bees: coffee and citrus flowers lace their nectar with a dose too weak for the bees to taste, yet strong enough to fix the flower's scent in their memory.

Which Amazonian seed, a staple of South American soft drinks, holds more caffeine than a coffee bean?

Guarana seeds are far richer in caffeine than coffee beans, weight for weight, which is why their extract turns up in so many energy drinks.

Members of which church follow a health code that bans 'hot drinks', meaning coffee and tea, but never mentions caffeine?

Latter-day Saints: their revelation on health bars 'hot drinks', which leaders read as tea and coffee, and says nothing of caffeine, so in 2012 the church corrected a TV report claiming members may not have caffeine.

Which famous writer handed a young chemist a box of coffee beans to analyse in 1819, leading to the discovery of caffeine?

Goethe had invited the young Friedlieb Runge to demonstrate how a plant extract widens a cat's pupils, then sent him off with the beans, from which Runge soon isolated caffeine.

Which fruity malt liquor lost its caffeine in 2010, the year the FDA called the stimulant an 'unsafe food additive' in alcohol?

Four Loko was reformulated in December 2010 after several states banned it; the FDA had warned that caffeine can hide the cues drinkers rely on to judge how intoxicated they are.

The US government once seized 40 barrels and 20 kegs of which product, alleging its caffeine was 'injurious to health'?

Coca-Cola syrup: the 1909 seizure became a Supreme Court case named after the barrels and kegs, and in 1916 the justices overturned the company's early win and sent it back for trial.

Which English king tried to shut down England's coffeehouses?

Charles II called the coffeehouses haunts of 'idle and disaffected persons' who spread false reports about his government, but the ban raised such an outcry that it was withdrawn.

About how much caffeine a day do European and US regulators consider safe for a healthy adult?

About 400 mg: Europe's food-safety authority and the FDA both cite that figure for healthy adults, while the FDA says seizures can follow when around 1,200 mg is swallowed quickly.

Ounce for ounce, which coffee drink delivers the most caffeine?

Espresso is by far the most concentrated, yet a single shot holds less caffeine than a mug of drip coffee simply because the serving is so small.

Which body moved caffeine off its list of banned substances in 2004 and onto a watch list?

World Anti-Doping Agency: tests in the four years after the change found caffeine in about three of every four urine samples taken at competitions, but hardly any above the old limit.

Which caffeine product, linked to at least two deaths, did the FDA curb with new guidance in 2018?

Pure caffeine powder: one teaspoon can hold as much caffeine as 28 cups of coffee, and the FDA says a safe serving is too small to measure with kitchen spoons.

About how long does a healthy adult's body take to clear half of a dose of caffeine?

About 5 hours, within a normal range of three to seven, so half of a mid-afternoon coffee can still be circulating at bedtime; a newborn needs days to do the same.

Regular smokers tend to drink more coffee, possibly because tobacco smoke does what to caffeine in the body?

Speeds up its breakdown: chemicals in the smoke rev up the liver enzymes that clear caffeine, so a smoker gets a shorter lift from every cup.

Caffeine citrate is on the WHO's list of essential medicines for treating which condition?

Apnea in premature babies: their immature brains sometimes stop sending the signal to breathe, and caffeine stimulates the brain's breathing centres until they catch up.

Regular caffeine consumption may reduce the risk of which neurological condition?

Parkinson's: large long-term studies keep finding fewer cases among people who take in more caffeine, and in animal experiments the drug shields the brain from the damage.

Which over-the-counter pain reliever combines aspirin and acetaminophen with caffeine to boost its effect?

Excedrin: pooled trials found that 100 mg or more of caffeine lets roughly 5 to 10 more people in every hundred get good relief from the same dose of painkiller.

Caffeine was once used as a second-line treatment for which condition?

ADHD: caffeine beat placebo in trials but lost out to drugs such as methylphenidate, and people with ADHD still tend to drink more of it, perhaps to self-medicate.

Which amino acid found in tea has synergistic alerting effects when taken with caffeine?

L-theanine: pooled trials found the tea compound and caffeine together sharpened alertness and attention-switching in the first two hours after a dose, and supplement makers sell the two as a pair.

Which British financial institution grew out of a coffeehouse where ship owners and merchants met to trade news?

Lloyd's of London began in Edward Lloyd's coffee house, where shippers and underwriters met to insure voyages, and it still carries the name of the man who served the coffee.

According to a popular story, which leader tasted coffee, condemned by clergy as 'Satan's drink', and approved it for Christians?

Pope Clement VIII is said to have tried a cup when his advisers urged him to ban it, and to have joked that the drink was too delicious to leave to the infidels.

Which symptom is the hallmark of caffeine withdrawal?

Headache typically sets in within a day of the last cup, when blood flow in the brain, held down by caffeine, rebounds; it can linger for several days.

Which Indonesian island, where the Dutch planted coffee in the 1600s, became a nickname for the drink itself?

Java: the Dutch shipped its beans to Europe as 'Java coffee', a name later clipped to 'java', and by the early 1900s the word meant any coffee at all.

Ludwig Roselius's first commercial decaf process washed the caffeine out of the beans with which chemical, now a known carcinogen?

Benzene: Roselius's Kaffee HAG process rinsed moistened green beans with it to carry off the caffeine, and decaf makers dropped it once its dangers were understood.

Decaf coffee was first made commercially in the 1900s, as Kaffee HAG, by a company in which country?

Germany: a Bremen coffee merchant launched the first commercial decaf there, and the caffeine that decaf factories strip out is sold on to makers of soft drinks.

The Swiss Water decaffeination process is distinctive because it avoids what?

Any organic solvent: only water and charcoal filters touch the beans, and despite its name the process is now run from a plant in British Columbia, Canada.

The coffee word 'mocha' comes from the name of a port in which country?

Yemen: its Red Sea port of Mocha shipped out coffee grown further inland, so 'mocha' meant fine coffee long before it came to mean a mix of coffee and chocolate in the 1800s.

Theobromine, a relative of caffeine and one of its metabolites, is the principal alkaloid in which food?

Cocoa beans: theobromine is the main reason chocolate can poison dogs, which break it down much more slowly than people do.

Which caffeine-rich nut is chewed across West Africa to restore vitality and ease hunger pangs?

Kola nut: its caffeine-rich extract flavoured the early cola soft drinks, which took their name from the tree.

A bombilla is the metal filtering straw used to sip which South American drink?

Yerba mate is brewed in a gourd packed with dried holly leaves and hot, not boiling, water, and one server refills it so the whole group can drink in turn from the same straw.

Gyokuro, a pale green tea, packs more caffeine than many darker teas partly because its bushes are grown how?

Under shade: the tea gardens are covered for weeks before picking, and the light-starved young leaves build up extra caffeine, which is why a tea's colour says little about its kick.

A standard 250 ml can of Red Bull has roughly as much caffeine as which of these?

One cup of coffee: the can carries less caffeine than many mugs of drip coffee, and across all age groups energy drinks add little to total caffeine intake.

Red Bull was adapted from Krating Daeng, a sweet tonic sold to truck drivers and labourers in which country?

Thailand: Chaleo Yoovidhya's tonic was selling there when Dietrich Mateschitz, a visiting toothpaste marketer, found it cured his jet lag and partnered with him to carbonate it for the West.

In which country is Red Bull GmbH headquartered?

Austria: the company launched the drink there in 1987, selling what had been a labourers' tonic as a trendy, upscale drink at ski resorts, and it is still run from the village of Fuschl am See.

According to The New York Times, 'the energy drink as we know it' was born in which country in 1962?

Japan: Taisho's Lipovitan D went on sale there in 1962 in minibar-sized bottles, pitched at truck drivers and factory workers who had to stay awake through long shifts.

Which energy drink was launched in 2002 by Hansen Natural, a California firm known for fruit juices and natural sodas?

Monster so outgrew the juices that the company renamed itself Monster Beverage in 2012 and later handed its older drinks to a soft-drink giant.

Which 2-ounce product, launched in 2004, kicked off the 'shot' offshoot of the caffeinated-drink market in the US?

5-Hour Energy: its founder tried a 16-ounce energy drink at a 2003 trade show, shrank the idea to a 2-ounce shot, and by 2012 its retail sales were put at $1 billion a year.

Besides caffeine, which compound is the signature ingredient of energy drinks such as Red Bull?

Taurine takes its name from taurus, Latin for bull, because chemists first isolated it from ox bile in the 1820s.

Which company pulled its new caffeinated gum, Alert, in 2013 after the FDA said it would investigate caffeine added to foods?

Wrigley halted production and sales of the gum while the FDA looked into caffeine turning up in more foods; a year earlier the agency had warned a firm selling a caffeine inhaler.

According to legend, coffee first reached which country hidden in a bouquet from the wife of French Guiana's governor?

Brazil: Francisco de Melo Palheta is said to have charmed her into slipping him the seeds her husband refused to export, and by the 1840s the country dominated world coffee.

Which citrus soda packs more caffeine per can than a regular cola?

Mountain Dew began in 1940s Tennessee as a mixer for whiskey, and its name is old slang for moonshine.

UK and US health bodies advise which group to keep caffeine under about 200 mg a day?

Pregnant women: the body clears caffeine far more slowly late in pregnancy, and it crosses the placenta to a baby that can barely break it down at all.

French missionaries planted the first coffee trees in which Southeast Asian country in the 1800s?

Vietnam: the missionaries brought arabica, but its farmers now grow mostly hardier robusta, the bean with nearly twice the caffeine, and by 2023 the country was the world's second-biggest coffee grower.

Which kind of chocolate bar carries the most caffeine?

Dark chocolate: the caffeine sits in the dark, non-fat part of the bean, so a milk bar has about a quarter as much and white chocolate, made from the fat alone, has next to none.