It's no death wish, just a kick-up-the-backside coffee

Wake up and smell the strongest coffee in the world. And it comes from Cape Town.

The aptly named Black Insomnia coffee company has produced a roast that contains the maximum recommended daily caffeine allowance in one small hit.

Independent laboratory tests found Black Insomnia - with 17524mg of caffeine per kilogram - is 33% stronger than its closest rival, Deathwish Coffee, in the US . And it seems that everyone wants that extra boost of energy.

Established only 10 months ago, the company has gone global and its super-charged product is now available through retailer Amazon.

Black Insomnia founder and coffee addict Sean Kristafor said by October last year, just four months into the business, the company was already supplying 43 countries.

"On October 4 I got an order from a coffee shop in Finland," said the 45-year-old entrepreneur. "The owner later posted on Instagram that it was the best coffee he had ever tasted."

The Brazilian and Ugandan robusta coffee bean blend became available in the US in January.

Kristafor, who starts his work day at 4am, drinks two cups of his high-energy blend and at least two to three normal cups of coffee.

"I won't have a Black Insomnia after 3pm though. I would never sleep."

He said his blend might pack a mean punch but, actually, it is a mellow-tasting brew.

"It's surprisingly smooth, a medium blend with a nutty taste," he said. "There's no need to add sugar. People expect dark and bitter and are pleasantly surprised. The hit comes five minutes later."

Kristafor described it as "probably the most potent hit you can get legally".

Kristafor retired in 2014 with the aim of taking it easy, but soon got bored.

He said: "I spent lots of time bouncing around local coffee shops. There's a great coffee culture in Cape Town and it's all about craft and taste, yet there was no emphasis on getting a good hit."

He partnered with coffee roaster Gerald Charles to make Black Insomnia.

"I thought I would supply a couple of outlets in the area and let the business tick along," he said.

Kristafor is negotiating distribution agreements with Australia, the UK and the United Arab Emirates. The company is also producing caffeine-added mineral water and a sugar-free energy drink.

"We are quite small," he said. "Me, the roaster and about seven others. We are flying by the seat of our pants and building the airplane as we do it."