News release

From: Springer Nature

Brewing up a quick test for great coffee

A quick, simple test to measure the strength and roast of black coffee is reported in Nature Communications. The approach could offer a reliable way to quickly assess coffee flavour characteristics without requiring complex sample preparation.

Existing methods to evaluate coffee typically rely on tasting panels or indirect measurements, such as estimating the amount of dissolved material in a sample. However, these methods cannot distinguish chemical differences caused by roast level or brewing choices. Other laboratory techniques can identify individual molecules, but these are slow, expensive, and often impractical for routine use.

Christopher Hendon and colleagues report a method to rapidly assess the strength of black coffee using an electrochemical test called cyclic voltammetry. The test involves applying a voltage to and measuring the current passed as the coffee responds to the electric field, allowing for differences in strength and roast to be isolated. The authors observed a linear relationship between beverage strength and total electrical charge, with these signals also becoming weaker as the roast of the samples became darker. This weakening is attributed to the roast‑dependent molecules, including caffeine, sticking to the platinum electrode during the measurement. The methods were validated through comparison with colour and flavour descriptions from a UK-based roastery’s quality‑control process. The authors suggest that this test could help to distinguish between batches of brewed coffee that look identical and have similar dissolved‑solid readings but differ in flavour.

These results suggest that this test could serve as a sensitive and reliable way to assess coffee composition, complementing existing tools used by the industry.