It says that refraction does not cover everything.
> By sampling features in the electrochemical response that are affected by the ensemble chemical composition of the coffee rather than measuring the concentrations of individual molecules, this approach captures quantitative information about both roast color and beverage strength. These two properties drive the sensory profile of the beverage, thereby allowing this analytical technique to exceed the insights provided by refractive index measurements and provide additional quality information that correlate with flavor.
alt Hacker News
It says that refraction does not cover everything.
> By sampling features in the electrochemical response that are affected by the ensemble chemical composition of the coffee rather than measuring the concentrations of individual molecules, this approach captures quantitative information about both roast color and beverage strength. These two properties drive the sensory profile of the beverage, thereby allowing this analytical technique to exceed the insights provided by refractive index measurements and provide additional quality information that correlate with flavor.