Comparison between the methylene blue test and the ion magnesium release test to evaluate the yeast quality in the craft beer fermentation process

The obtainment of beers of good quality and with stable characteristics is the goal of craft and industrial beer producers. Re-pitching is quite common in breweries to reuse yeast in sequential beer productions, nevertheless the stress effect of this practice on yeast physiological state is well known. The yeast supply and its physiological conditions are crucial points for small breweries unprovided of sophisticated equipments. The possibility to evaluate in a short time the yeast metabolic condition is an important tool to ensure good fermentations in order to get uniform and stable products. in this work different tests to verify the quality of dry yeats were compared, moreover and evaluation on sequential beer fermentation was carried out using the magnesium ion release test. This is a fast and reliable test of the dry yeast quality which could be used in breweries.