A coffee compromise

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We all love coffee and I imagine that most of us secretly love the wonderfully stimulating effects of caffeine too, even though we know that it’s a drug and even though we’re probably addicted. If we don’t drink enough, we suffer. If we drink too much, we suffer. So what to do?



Keep drinking caffeinated coffee, but stick to safe limits. Easy, right? In theory, but there’s a problem – what is a ‘safe’ amount of caffeine and how does it translate in practical terms?

The Coffee Universe investigates.

First of all, it’s very important to acknowledge that safe caffeine limits will vary from person to person, depending on your weight, health and a whole range of other factors. One website www.caffeineinformer.com has a calculator which takes note of your weight and your preferred caffeine drink then reveals your safe limit – and how many it would potentially take to kill you. For the record, death-by-espresso would happen for me after 113 shots in a single day.

On a more serious note, experts in studies across the world generally recommend no more than 300-500mg of caffeine per day – for healthy adults. The trouble is that very few people actually understand how that number translates in real life – me included, until I studied for this article.

Coffee mug espresso

So now it’s quiz time. Which of the following hot drinks holds the biggest caffeine boost?

  • A shot of espresso
  • A cup of green tea
  • A can of diet cola
  • A cup of black tea
  • A mug of brewed coffee

Drum roll…and the worst offender is…brewed coffee. A standard 8oz/237ml mug is likely to contain between 95-200 mg of caffeine compared to a 75mg maximum in a shot of espresso – according to figures provided by the Journal of Food Science.

So what comes next? Tea, green and black. There’s an ongoing debate about which tea contains more caffeine – it depends on brand and brewing time – but figures show green tea’s base point is 24mg per mug while black tea can start at just 14mg. But green tea’s upper limit of 45mg can’t be matched by black tea’s whopping 70mg – almost the same as a shot of espresso.

I’m surprised cola comes last in line with half the caffeine levels of tea. For the record, energy drinks contain on average 70-100 mg of caffeine per can, while tiny bottles of concentrated energy ‘shots’ can fire 200mg of caffeine into your system at once, around half the daily dose.

So which drink is best? The choice is yours – but if you choose to stay caffeinated, stay safe.