Estudio y obtención de volátiles y su relación con diferentes variables físicas para la obtención de perfiles de fermentación en fermentadores de mosto de cerveza.

– Beer is today the most widely consumed alcoholic beverage in the world, and third if soft drinks are considered. It is produced by alcoholic fermentation of the sugars present mainly in barley malt, and sometimes other cereals, by the action of the yeast Saccharomyces cerevisiae or pastorianus, at temperatures (18 - 24 ° C) and specific levels of pH (5.1 - 5.5). This work is given in the framework of collaboration between UPM, CENIM, and La Cibeles, and aims to develop a low cost ̈electronic nose ̈, to find the characterization of certain important attributes during alcoholic fermentation. We have developed an electronic nose, with three sensors for volatiles (CO2, O2 and ethanol), and two sensors for temperature (headspace and wort). We designed and configured a digital device based on digitizing modules (ADAM and ArduPLCm) that capture and save the data. The whole system is programed as a virtual instrument using LabView, and finally dedicated smoothing routines in Matlab environment are programed for processing. Smoothing makes use of a Savitzky-Golay with corresponding result discussed. The system has been installed at La Cibeles facilities, and two fermentation processed have been evaluated with the system at a small scale level (15 liter). The values of oxygen, carbon dioxide, ethanol, wort beer temperature, and the temperature of the air-chamber headspace have been monitored accordingly. Due to maintain business secrecy, it is not possible to detail issues related to recipes, ingredients, quantities, hops, and specific time, of how different beers are brewed, yet the feasibility of the system for monitoring fermentation is clear from these initial results. Among the most relevant results, we have seen how the influence of temperature has provoked a vigorous fermentation process. It has also been observed, the relationship between oxygen consumption and production of carbon dioxide, although there is no direct stoichiometric equation that relates the two phenomena, both occur very close ...