CIEDE2000 colour difference value as a parameter for tracing the ageing process on wood aged spirits

Abstract

It is quite common nowadays to carry out analyses which allow to control the ageing of spirits that are aged in wood casks. Many control parameters have been previously studied, such as the concentration of different phenolic compounds or the Total Polyphenol Index, in order to better understand the ageing process of wood aged spirits. On the other hand, it is frequent to analyse as a physical parameter the colour of those spirit samples, by stating them as an array of three coordinates from various colour spaces as CIE L*a*b* or CIE L*C*H*. 

In year 2001, the International Commission of Illumination proposed and/or modified various mathematical formulas for measuring the colour difference between two different samples and named that parameter as CIEDE2000. This value allows to quantify, with a number within a range from 0 to 100, the visual difference between two colours and, at the same time, it stablishes some value ranges which give some information about how easy is by an observer to differentiate them by eye. 

Due to the ageing process in wood casks of alcoholic beverages produces changes on the intensity and on the hue of the colour, in the present work we proposed to study, by analysing the colour differences between various samples aged in different times, if the CIEDE2000 parameter could be used as a parameter on the tracing of the ageing process. 

To this end, kinetical analyses and statistical regressions were carried out over different wood-aged spirits samples, obtaining good R2 values in return, stating that colour difference values could be used as parameters to study and better comprehend the ageing process of beverages in wood casks.