So you like your coffee strong…what does this really mean?
Let’s consider how we are defining strength; it could refer to the amount of caffeine, or the fullness of flavour or body in your cup. Surely stronger tasting coffee must also be higher in caffeine? This isn’t necessarily the case. Here are some facts:
- All Arabica coffees have about the same amount of caffeine in their beans. Beans roasted for longer tend to taste stronger but the roast time doesn’t alter the caffeine concentration. Roasting aside, some beans are naturally fuller in flavour, for example Sumatra; but these are no stronger in caffeine than milder tasting beans from South America
- Robusta is the more resilient, cheaper and less tasty cousin of the Arabica bean and is therefore often found in poor quality coffee blends. Robusta beans have twice as much caffeine as Arabica. Some high-roast ‘Italian’ or ‘French’ blends will therefore be stronger in taste and also caffeine as the robusta bean is sneaked in under the disguising cloak of a ‘full’ roast
- Filter coffee has slightly more caffeine than espresso, assuming the weight of coffee being brewed is the same. Caffeine is water soluble so a longer contact time between the coffee and the water will extract more of it. In fact cold-brewed coffee, extracted over eight hours probably has the most caffeine in the cup, assuming all other things being equal
So if you want a stronger coffee, what should you look for?
- If you want a caffeine hit then you could seek a coffee blend containing robusta beans; but beware, robusta tends to taste of burned tyres!
- Choose ristretto the shorter more intense version of the espresso, which creates just 30ml of liquid extracted from 18g of ground coffee. The same 18g of coffee would make nearly 300ml of brewed coffee in filter or pour-over. Whilst the caffeine content in brewed coffee will be slightly more, the volume of liquid is significantly higher so you could have two ristrettos with nearly twice the caffeine but still have only drunk one fifth of the liquid
- If it’s not the caffeine but a big bold cup you’re after then you could either choose a fuller roast or buy beans from a region that develops a naturally stronger tasting bean - for example Asia or India or naturally processed beans from Africa.