Influence of the Processing and Raw Material in the Physicochemical Characteristics of the Lager Beer produced in the Microbrewery

Abstract

In this work the influence of processing and raw material on the physicochemical characteristics of Lager beer produced in a Microbrewery was studied by the application of appropriate statistical tests (ANOVA and Pearson's linear correlation). For this purpose, physicochemical analyzes of pH, acidity, bitterness, color and alcoholic degree were carried out in samples collected at the end of the main stages of production process (brassage, boiling, fermentation and maturation) and the data were analyzed statistically. The results of the Analysis of Variance of the processing and sampling factors indicated that there were significant differences in all stages of the beer production process (p <0.05), between the samples analyzed (p <0.05) and a significant interaction effect (p <0.05) between the processing and sampling factors for all physicochemical characteristics evaluated. The differences observed between the processing steps and between the analyzed samples can be explained by the alkalinity of the water used in the manufacture, the changes of batches of raw material and the changes in the beverage formulation. To better understand how the processing steps, raw material changes and formulation changes affect the physicochemical characteristics of prepared Lager beer, linear correlation analyzes were performed at the 95 % confidence level. Significant negative linear correlations between acid malt proportion and values of pH of brassage step (r = -0.983, p = 0.000), boiling step (r = -0.950, p = 0.000) and maturation step (r = -0.949; p = 0.000) and inversely significant positive linear correlations with the traditional malt ratio and the pH values of the brassage stage (r = 0.958, p = 0.000), boiling stage (r = 0.898, p = 0.001), fermentation stage (r = 0.749; p = 0..020) and maturation stage (r = 0.909; p = 0.001) showed that the type of malt used, as well as the proportion adopted in the beverage formulation has a great influence on the pH values of all stages of the Lager beer brewing process. A significant positive linear correlation was observed between the pH values of the boiling stage and the bitterness of the maturation stage (r = 0.717; p = 0.030) suggesting that the Lager beer bitterness is strongly influenced by the pH values of the boiling stage. Similarly, the color of Lager beer is directly proportional to the proportion of traditional malt adopted in the formulation as visualized by the positive linear correlation (r = 0.636; p = 0.000) among these variables. A one-factor Analysis of Variance showed significant differences between the samples of the maturation stage (p <0.05) for all the physicochemical characteristics studied. Despite the verified statistical differences, the evaluation of the physicochemical parameters in the beer samples of stage of maturation showed an adequate quality according to the standards cited in the literature for the Lager beer style.