Research into mathematics of coffee finds answer to perfect brew

16 Nov 2016

Drip filter coffee. Image: iPranoffee/Shutterstock

New research into the surprisingly complicated world of coffee mathematics has led to an Irish team of scientists discovering what should make the perfect brew.

It is a multibillion-dollar industry that provides ‘black gold’ to millions of people across the globe, but few are aware that the making of a perfect cup of coffee is intrinsically linked to mathematics.

In total, there are 1,800 chemical compounds found in coffee, and this resulting complexity means that it can be surprisingly easy to make a truly terrible brew, or one that could be unlike anything you have ever tasted before.

New ground for bean research

In order to better understand the advanced mathematics involved – and taste some nice coffee in the meantime – a group of Irish-led researchers involved with the Society for Industrial and Applied Mathematics (SIAM) got on the case.

The study led by PhD researcher Kevin Moroney from the University of Limerick (UL) developed a new multi-scale model of coffee extraction from a coffee bed that could be used by drip filter machines.

This wouldn’t be the first mathematical study to find the perfect brew, but Moroney and his team are one of the first to look at how it might work in a drip filter brewing system.

Of the 18m coffee machines sold commercially in Europe, it is estimated that 10m of these are of the drip filter variety that pours hot water over ground coffee beans, then using gravity to extract the coffee solubles into the cup.

Coffee brewing

From left: Lead author Kevin Moroney of UL and Dr William Lee measuring coffee concentration using a refractometer. Image: University of Portsmouth

A ‘hideously complicated’ process

In a previous paper, Moroney and his team analysed bed dimensions, flow rates, grind size distribution, and pressure drop in a drip filter machine, at the optimal temperature range of between 91 and 94 degrees Celsius.

However, the team’s new research has crunched the numbers to find that the size of a coffee grain plays a crucial role in determining the quality of the coffee.

The findings made by the team will likely be of interest to makers of drip filter coffee machines as they can tell what the ideal filter shape is, as well as what the flow rate of the water should be through the filter bed.

Having described perfect coffee making as a “hideously complicated” process, co-author of the paper, Dr William Lee from the University of Portsmouth, said maths offers a solution.

“By using mathematical analysis, we can begin to tell the story of which elements, and in what order, lead to the best coffee – we are now one step closer to the perfect cup of coffee,” he said.

Colm Gorey was a senior journalist with Silicon Republic