Prediction of bitterness and alcoholic strength in beer using an electronic tongue

An electronic tongue based on an array of electroactive conducting polymers was developed for the analysis of beers.The principal component analysis (PCA) of the electrochemical signals obtained by immersing the array of electrodes in 21 lager beers (dark and pale; with alcohol and alcohol free) has provided a clear discrimination between dark and pale beers and also between beers with and without alcohol. The correlations between redox processes observed in the electrodes and the iso-α-acids concentration and the alcoholic degree have been found using partial least square regression (PLS2). The Root-Mean-Square Error of Prediction (RMSEP) values for alcoholic strength and iso-α-acids prediction model were 0.603 (%vol) and 9.021 (mg L−1), respectively.