WTF Is Optimal Extraction?

Each issue, Caffeine uncovers some of the mysteries behind the coffee in your cup. In Part 4, Chris Bartlett explains how extraction rates affect its characteristics.

- Chris Bartlett

Without caffeine, coffee – both the plant and the drink – would surely never have made it out of Ethiopia. Its euphoric, energy-giving effects are what has caused coffee to be cultivated and consumed around the world for centuries. It keeps whole workforces going, stimulating both body and mind – indeed, it’s why you’re reading Caffeine magazine right now.

But caffeine is far from the only essential compound in your cup. The composition of any cup of coffee, from the most revered single estate to the harshest of dark-roasted blends, is complex. Each one may contain as many as a thousand distinct compounds, each with its own properties and its own effect on your drinking experience.

Caffeine belongs to a class of compounds known as purines. Its structure means it binds to adenosine receptors in the nervous system, and in doing so blocks the effects of adenosine – which is how it reduces feelings of drowsiness and increases alertness. The structure of a molecule also determines its physical behaviour in water and how we perceive that when drinking.