Calculate wine acidity using digital image analysis

The acidity of a wine is a parameter that must be controlled, not only in the final product, but also throughout the production process. The methods currently used can involve a great use of reagents and instruments that probably in some cases are not available to the interested party or are not profitable.

To alleviate this situation, Aritz Martínez Rodríguez, a graduate of the Faculty of Chemistry of the University of the Basque Country (UPV/EHU) and who is now at the Complutense University of Madrid (UCM), in Spain, has devised, in his Work on End of Degree, a new method of digital image analysis that does not require excessive use of reagents. Compared with the rest of the techniques, the volume of reagents used to determine the concentration of tartaric acid (total acidity) is 96-98% less than in the titration tests, in which the pH is calculated through color change. , and 96% lower than in potentiometry tests.

Aritz Martínez has shown that this new method is highly accurate; does not have any significant difference in precision with respect to these two techniques, being possible to put it into practice in areas where it is required to know the acidity of a wine, such as in wineries during the alcoholic fermentation and malolactic fermentation processes (process of making wine). wine to lower the acidity) as a follow-up, or the quality control of the product to be sold afterwards. Replacing any of these methods, therefore, can be an economic improvement without losing precision and accuracy. In addition, the use of the Matlab code that has been developed allows the method to offer a fast answer without the need to perform any mathematical treatment, making this method easy to perform.

Aritz Martínez considers that, further developing the technique, it would be possible to design a kit so that the user who wants to use this method does not need additional material or instruments. “The kit would provide the microtiter plate necessary for the test and the bottles with the reagents necessary for its performance, as well as an instrument to deposit the volumes of these in the wells of the plate. This study is carried out with the use of micropipettes for the addition of volumes to the microtiter plate, a material that could be replaced by a dropper to facilitate the performance of this technique. It is true that this substitution should be carried out in the case of not needing a great precision in the measurement ”, he concludes.

Aritz Martínez in a laboratory of the Faculty of Chemistry of the UPV/EHU. (Photo: UPV/EHU)

Aritz Martínez Rodríguez’s Final Degree Project is entitled “Automation by image analysis of the measurement of acidity in different alcoholic beverages”. She did it under the direction of Professor Maider Vidal from the Department of Applied Chemistry of the Faculty of Chemistry of the University of the Basque Country. (Source: UPV/EHU)