The control of specific parameters during food manufacturing process is a very important task to ensure high quality and safety of final food products. Ethanol is one of the most important analyte associated to the state of the health of the grapes; its presence reveals the starting of premature alcoholic fermentations by indigenous yeasts that can interfere during winemaking process. Therefore, an accurate and fast measurement of ethanol concentration during delivery of grapes is highly needed in the wine industry. The use of biosensors as an analytical method to determine the presence of ethanol represents an attractive alternative for the food industry because of their high sensitivity, selectiveness, ease and rapidity of use. Previous studies (Tsai et al., 2007; Park et al., 1999) reported the development of screen-printed amperometric ethanol biosensors using alcohol dehydrogenase (ADH) and β-nicotinamide-adenine dinucleotide (NAD+) cofactor. The enzymatic reaction produces acetaldehyde and β-nicotinamide-adenine dinucleotide, reduced (NADH).. The direct electrochemical oxidation of NADH at bare electrodes only proceeds with high overpotentials at 1 V vs. silver/silver chloride reference electrode (Ag/AgCl) and leads to fouling of the electrode surface. In fact, the overpotential higher than 0.8 V vs. Ag/AgCl leads to the oxidation of other electroactive species present in the food samples that interfere with the accurate determination of ethanol (Bartlett et al., 2002). To avoid this problem, redox mediators and conducting polymers have been employed for NADH oxidation at lower potentials (Prieto-Simòn et al., 2004; Jiang et al., 2009). In …