Revealed: the science behind the perfect espresso

If, like us, you’re always chasing perfection in your brew then you’ll be interested to hear that US scientists have revealed what they believe to be the formula for making the ideal espresso.

Conventional wisdom states that a finer grind will give a stronger, more reliable brew, as each coffee particle has more surface area from which to extract the flavour. A team of mathematicians and physicists, including members from the UK, Ireland, Australia and Switzerland, are now challenging this contention. They’ve discovered that actually, the reverse is true – you need fewer coffee beans, more coarsely ground, to give a result that’s more consistent and just as strong.

Although the ‘perfect espresso’ is a fairly subjective term, researchers were aiming to get the same result every time with as little variation as possible. They put together a mathematical model with several variables, such as the amounts of coffee and water, the fineness or otherwise of the grounds and the water pressure, and modelled the predicted results. They discovered that grinding the beans very finely could actually be counterproductive, as grounds became clogged and the water couldn’t reach some of them at all, giving a result that varied in strength.

After much experimentation, the team produced a formula to maximise the amount of flavour extracted from the beans which would yield consistent results from cup to cup. This involves using a coarser grind, and less water.

One of the co-authors of the report, Jamie Foster, a mathematician at the University of Portsmouth, says that the results are important not only for the consumer but also for the coffee industry as a whole.

Here at the Wholesale Coffee Company, we’ve got everything you need to make your own version of the perfect espresso. To find out more, take a look at our main website at