The same study into high street coffee found that independent coffee houses were much more similar in their caffeine levels - but we want to dig a little deeper. We've been asking - what about the coffee you brew at home, and is there more caffeine in different beans?
What is caffeine?
First things first, we need to understand the chemical itself. Caffeine is a natural insecticide - it deters bugs from eating plants, and in high concentrations, will kill them off entirely. As far as nature is concerned, this is really all that caffeine is good for!
It's also found in much higher concentrations in Robusta than in Arabica beans, which explains why Robusta is a lot easier to grow and get larger yields from. Arabica coffees, whilst generally a lot tastier, are more susceptible to insect damage.
All in all, this is the reason why lots of lower-grade Robusta coffees pack more of a caffeine punch. No surprise, then, that Costa Coffee use Robusta in their blends, whereas Starbucks only serve Arabica. Those news articles make more sense now, don't they?
How do I make strong coffee at home?
We're often asked about how to make stronger coffee at home - whether that's through different methods like the Moka Pot and AeroPress, or recommending which beans to buy. The truth is, if you want stronger coffee, you simply need to extract more coffee. There are two ways of doing this. Firstly, you could use a recipe which calls for a higher concentration of coffee. We work with ratios with our brew guides, for example - 1g of coffee for every 18g of water in an V60 brew (a 1:18 ratio). For a stronger brew (and more caffeine), you could use a 1:16 ratio.The other way is to extract more from the same amount of coffee. If you had a 1:16 ratio for your AeroPress brew but ground it very finely, your hot water would extract more from the surface area of the coffee than if you ground it very coarsely. Some brewers, like the Tricolate, allow you to get super-high extraction yields, using very little coffee. Great if you want a well-extracted brew, and use fewer beans! We've estimated that your coffee will go about 30% further brewing on the Tricolate.
Do dark roasts have more caffeine?
This is an interesting question, and the simplest answer is 'not really'! What you can say for sure is that a darker roasted coffee has more of a perceived strength than a lighter one: our Rich Roast versus Two Stories, for example. The well-developed, full-bodied notes of a traditional dark roast are more likely to linger and pack a punch than a fruity filter roast.
The reality is that all Arabica coffees have a very similar level of caffeine, and if all the factors we mentioned before were the same, you'd see a negligible difference from one cup to the next. So, while the caffeine might be about the same, you'll feel like you're getting a bigger kick from a well-brewed dark coffee (like a thick-bodied Rich Roast in a Moka Pot, for example). There's a lot to be said about the power of the mind! Even our Sparkling Water Decaf can be deceiving: its roast style means that it's very like a traditional espresso roast, despite having passed very strict tests when going through its decaffeination process.
So there you have it - the main points to take away are that Robusta is more caffeinated than Arabica, and the brew method you choose will help you get the most out of your beans. Wondering where to start? Take our Coffee Match Quiz here!