An Electrochemical Appraisal of Coffee Qualities

TL;DR

This study demonstrates that cyclic voltammetry can rapidly and directly measure coffee strength and roast level in situ, providing a quantitative link to flavor without extensive sample prep.

Contribution

It introduces a novel electrochemical method using cyclic voltammetry to quantify coffee strength and roast level directly from the beverage.

Findings

Current in voltammetry correlates linearly with coffee strength.

Suppression of electrochemical features relates to roast color.

Method decouples beverage strength from roast level.

Abstract

Despite coffee's popularity, there are no quantitative methods to measure a chemical property of a black coffee drink in situ and relate it to a flavor experience. Here we show that cyclic voltammetry can be used in coffee without any additional sample preparation to directly measure the strength of a coffee beverage and, separately, how dark the coffee has been roasted; these two properties are implicated in the sensory profile of the beverage. We show that the current passed for the cathodic features that precede hydrogen evolution are linearly related to beverage strength. The same features are suppressed with subsequent cycling, and we show that the magnitude of suppression is directly related to roast color, which dictates the ensemble chemical composition and thus flavor of the beverage. Together, this voltametric analysis decouples beverage strength from roast color and offers a new strategy for rapidly assessing chemical properties of coffee that correlate to flavor.