Coffee jumpstarts the day for millions of people around the world, with many seeing their first cup of joe as an essential morning pick-me-up. But what happens if you triple your normal amount of caffeine, in one strong sip?

Enter: Skull Crusher Coffee, a high-caffeine coffee brand from Manchester that promises coffee lovers needing an extra kick that they’ll “never need to sleep again”. The brand claims that its java is about three times stronger than your average black coffee, packing 350mg of caffeine per cup which it says makes it the “world’s strongest coffee”. As the name suggests, it also has a skull and expletives on the front of its coffee bags.

Promising only 100 per cent natural, high-quality coffee beans, Skull Crusher Coffee says it gets these high-octane results by using a premium blend of beans and a special roasting process that has been specifically chosen to yield the highest caffeine content without compromising on flavour.

Of course, it’s worth noting that high-caffeine coffee is not for everyone. It can be a good option for those looking to increase their energy or fuel a particularly gruelling training session (as you would with a pre-workout supplement). But if caffeine can give you jitters, headaches, anxiousness or insomnia – we’d recommend staying well away.

How we tested

Following the instructions on the back of the bag for a cafetiere (the other brewing recommendation is a V60 coffee dripper), we added two heaped tablespoons of pre-ground coffee to 300ml boiling water and left it to brew for five minutes before slowly pressing the plunger. We then tried it again separately by using an Aeropress. Both times we tried the coffee black.

While sipping the coffee, we paid close attention to flavour as well as the product’s main draw; its strength and the effects that these high-caffeine beans promise. We also wore a Whoop fitness tracker to monitor our heart rate.

As an aside, coffee and its effects can vary greatly based on the drinker’s individual metabolism, genetics and built-up caffeine tolerance. Our tester normally drinks two to three regular coffees per day and according to the DNA test 23andme, our tester has two genes associated with consuming more caffeine (those are the CYP1A2 and AHR genes, science fans).

Looking for an intense caffeine hit with an equally dark roast flavour? Read on to see if the “world’s strongest coffee” is for you.

Skull Crusher Coffee

Buy now £14.99, Skullcrushercoffee.com

Rating: 5/10
Caffeine level: 350mg of caffeine per cup
Grind options: Ground or whole bean
Sizes available: 500g

Strength

As promised on the label, Skull Crusher Coffee is very, very strong. We’re focusing on caffeine strength here rather than bold flavours (which we’ll get into later).

After taking the first few sips, we felt the jolt from the extra caffeine within minutes, as well as an immediate boost in energy. However, after a little while we also experienced negative side effects including jitteriness and anxiousness – which are very rare for this tester. In terms of heart palpitations, we didn’t see any changes while monitoring via our fitness tracker.

While certainly potent, it’s hard to confirm whether this is in fact the “world’s strongest coffee”. Several other high-caffeine coffee brands around the world also claim to be the same (and use hard to confirm figures) – researchers at Caffeine Informer found much higher doses of caffeine from brands like Devil Mountain Coffee Company, for example. It’s also a hard title to prove as factors like processing and brewing time can affect caffeine levels.

To get into the maths of it, Skull Crusher Coffee estimates its beans have 350mg of caffeine per cup which is about the maximum amount of caffeine experts recommend in a day. By contrast, a regular cup of coffee normally has around 90mg of caffeine while a double espresso can rack up to 125mg per cup, according to the British Dietetic Association.

Flavour

Skull Crusher Coffee’s dark roasted scent hits your senses as soon as you open the bag. There are no subtleties over here. The in-your-face just-roasted smell is likely helped by the fact that the beans are in fact freshly roasted daily at the Manchester roastery.

Like the coffee’s supercharged caffeine-count, our tester found the taste similarly potent, with the flavours bitter and overly roasted. We wouldn’t choose to drink it again for its flavour, however fans of dark roasted coffee may find it more pleasant.

Sustainability

When it comes to supporting the environment, coffee brands know how important it is to go the extra mile these days and Skull Crusher Coffee is no different. In order to offset the carbon footprint of each purchase the brand has partnered with TR[1]BE who protect five mature trees and 100sq. metres of rainforest for every order placed on the site.

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The brand’s coffee is also Rainforest Alliance certified, a seal which is audited annually and takes a detailed look into environmental, social and economic criteria for protecting forests and improving the livelihoods of farmers and forest communities.

The verdict: Skull Crusher Coffee

While this reviewer in particular will not be brewing this coffee again, if you are looking for the strongest, darkest cup of coffee this side of the Atlantic and you have an extremely high tolerance for caffeine, Skull Crusher Coffee could be for you. At £14.99, it’s an affordable purchase (and it comes with a free mug), which also makes it a unique gift for coffee lovers.

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We tried the ‘world’s strongest coffee’ and it was a shaky affair

If you like your java dark and very, very strong, you may have just met your match

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How we tested