Though the global takeover of Starbucks and an explosion in third wave roasters have greatly improved coffee’s long time 20th century reputation as a dirt-flavored morning clock-punching aid, all the subtle notes of pink grapefruit and ginger in the world won’t erase the fact that plenty of people just use it as a caffeine delivery system. Which is why while some hip brands focus on things like “single-origin,” a few hardcore companies will always pander to the maximum pick-me-up crowd – aiming to conquer the crown of “world’s strongest coffee.” 
 
 Launched in 2016, Black Insomnia, a South Africa-based coffee company, is the most recent brand to claim that title, saying it has scientific proof that its blend is the most caffeinated in the world – with “dangerously high levels of caffeine” as the brand awkwardly boasts. And now, the king of caffeinated coffees is finally available in the US. 
 
 In the ongoing battle for the “world’s strongest coffee” crown, the unfortunately named Death Wish Coffee Company appeared to be the most legitimate previous king. However, according to Grub Street, Black Insomnia says that after an independent analysis of its beans and its competitors’ beans by a lab in Switzerland, Black Insomnia’s coffee was the “clear winner.” Caffeine Informer says Black Insomnia has 702 milligrams of caffeine per 12-ounce cup; meanwhile, Death Wish has 660 milligrams. For the record, both brands offer up more of the mild upper per 12-ounce serving than the 400 milligrams medical experts recommend you consume in an entire day. And to give this whole thing a bit of perspective, a “normal” 12-ounce cup of coffee will only have about 150 milligrams of caffeine. Meanwhile, a can of Coke only has 34 milligrams of caffeine. By comparison, the soda’s basically a sleep aid. 
 
 Though caffeine might be its primary selling point, Black Insomnia also wants customers to know its product is “strictly pure coffee” – apparently achieved from sourcing the most highly caffeinated Robusta beans (as opposed to the more flavorful Arabica beans) – all “without a burnt and high acidic flavor.” Its coffee still offers “a nice walnut and almost sweet taste profile,” the brand writes. 
 
 If all of this talk of super strong coffee has left you pining for a case of the jitters, good news, Black Insomnia is finally available in the US thanks to Amazon. A 16-ounce bag will set you back $19.99 – not a bad price all things considered… assuming you don’t factor in any future medical bills. ||||| If you are reading this over breakfast and want to be a part of the latest diet fad, then simple. Take a tablespoon, lift the butter dish and stir two great dollops of the yellow stuff into your coffee. Add a dash of oil - medium-chain triglyceride, if you’ve got some lurking next to the marmalade jar, and hey presto: one steaming cup of Bulletproof Coffee, otherwise known as the “fat black”. 
 
 The heady brew, caramel-brown with an unhealthy oily sheen, if done correctly, measures up to a whopping 500 calories per cup. It also tastes like the bottom of an industrial butter churn. But this is the new weight-loss craze that is sweeping the United States and now creeping into Britain. All hail the “new power drink of Silicon Valley”, coming to a café near you. 
 
 Joe Shute tries Bulletproof coffee Credit: Geoff Pugh 
 
 The coffee, whose lardy contents have left nutritionists shaking their heads in dismay, has been developed by tech millionaire Dave Asprey. The 41-year-old was once 21 stone, but that was before he discovered the “power of butter” at 18,000 feet during a hike near Mount Kailash in Tibet. 
 
 “I staggered into a guest house from the minus-10 degree weather and was literally rejuvenated by a creamy cup of yak butter tea,” so Asprey’s story goes. Now slimline, and still talking with the giddiness of somebody recovering from a bout of altitude sickness, he professes to be a “bio-hacker”: a man who can manipulate his own biology to gain an unfair advantage in business and life. 
 
 Bulletproof coffee is prepared with coffee beans, butter and oil Credit: Alamy 
 
 So far, so nonsensical, but the devotees to his Bulletproof Coffee are growing. In London, several cafés now stock the beverage, including Crussh, a branch of juice bars, which replaces milk with butter in its so-called Smart Coffee. The drink is prepared with coffee beans, two pats of butter from grass-fed cows and MCT oil (a coconut and palm kernel oil derivative). The standard price is £2.95; or for £3.65 you can add a dash of Bulletproof Brain Octane Oil. 
 
 This, Aga Mis, the manager of the Victoria branch tells me, is 15 times stronger than the regular brew. “We started doing it about four or five months ago. It is getting a lot more popular. It is the sort of drink that you develop a taste for. We sell about 10 a day. 
 
 Such concoctions, say the critics, encourage the worst in modern-day narcissism and will no sooner help you lose weight than a bacon butty. Incidentally, Asprey preaches an overall diet rich in saturated fat to be enjoyed alongside his coffee. 
 
 “There is no science that would back this up as a weight-loss tool,” says Dr Sally Norton, an NHS surgeon and leading UK weight-loss consultant. “The problem is we have a huge obesity epidemic where two thirds of us are overweight and one quarter obese. The more we try to lose weight, the worse it is getting. People are just desperate and don’t know where else to turn.” 
 
 Sian Porter, a spokeswoman for the British Dietetic Association, who first heard about fat blacks a few weeks ago, is similarly sceptical. “He has done one of the classic things that fad diets do by saying he has looked at thousands of studies. But it is about quality not quantity." 
 
 As for the taste of a buttery coffee, and the claim that the drink boosts “mental clarity”, who better to ask than the harried office workers of London walking the streets during a week of Christmas parties? 
 
 Lattes and cappuccinos and become passe Credit: Alamy 
 
 “All you can taste is the butter,” says Stuart Butcher, 40, who works in acquisitions and marketing. “Normally, I would just go for an americano, maybe with a bit of cold milk.” 
 
 Craig Timmis, a 33-year-old lawyer, decided to have a sip on his way back from lunch at a nearby Thai restaurant. “It tastes very weak, but there is a greasy film that definitely stays with you.” 
 
 “I love butter, I put it on everything, and I love coffee as well,” says Helena Kilduff, 26, an account manager. “But,” she says, regarding the droplets of oil formed on the surface, “definitely not the two together.” 
 
 In 2015, Asprey plans to open his first Bulletproof café in Los Angeles, but the people of Britain might take more convincing. Until then, viva the milk and two sugars, and save the butter for your toast. 
 
 
 
 This article was first published on Dec 18, 2014 and has been republished after researchers claimed that warnings against the consumption of butter should never have been introduced
– Tired of wimpy cappuccinos and limp lattes? Now you can jump-start your day with the "world's strongest coffee." At least that's the claim of the not-so-subtly-named Black Insomnia, which contends it has scientific proof its brew packs multiple times the punch of a normal cup of Joe. The South African newcomer boasts it has achieved "dangerously high levels of caffeine" by harvesting only Robusta beans, rather than the tamer Arabica variety. As for taste, which seems beside the point, the brand promises "a nice walnut and almost sweet taste profile," with nary a trace of "a burnt and high acidic flavor." You can be the judge (kind of): The company announced its beans went on sale in the US via Amazon last Friday, but it's currently listed as unavailable. It's apparently a hot contest for the global title of strongest coffee, with companies such as Death Wish in the running. Food & Wine gives context with this math: Caffeine Informer lists 351mg of caffeine in a 6-ounce cup of Black Insomnia, compared with 330mg for Death Wish. That's skirting the maximum 400mg per day that the Mayo Clinic recommends for "healthy adults." A normal cup packs a relatively paltry 70mg. Founder Sean Kristafor claims to have essentially reached the upper limit, with a press release warning competitors against attempting to "surpass this content in the interest of public health and safety." Further, he notes that while developing his coffee, "any blend that resulted in a higher caffeine content than 702mg [per 12 ounces] adversely affected the flavor and thus was rejected." (These students were given potentially lethal doses of caffeine.)