One of the main chemical reactions in beer brewing is is isomerization of hop alpha-acids and These compounds are responsible for the beer bitterness and its characteristic flavour. With its complex chemistry, hop has been the subject of deepened investigations for decades. The aim of this study was to found out if Differential Scanning Calorimetry and High Pressure Liquid Chromatography can give us further information on thermal behaviour of hop extracts during brewing.
COBISS.SI-ID: 4870264
Hop essential oils are of crucial importance for brewing industry, because they give beer its specific flavor and aroma. With intent to achieve desired aroma in beer, brewers need to know the composition of hop essential oils. At the Slovenian institute of hop research and brewing all analyses of hop essential oils are performed according to the Analytica-EBC regularly. With intent to optimize and shorten the time of analysis, and to obtain additional parameters a new method was developed that enable faster analytics for a single sample.
COBISS.SI-ID: 908919
Although beer evaluation runs with sensory experts, we cannot neglect the influence of the human factor and subjectivity. This problem could be solved with chemical analysis of the volatile part of beer aroma from which we can build a data bank for construction a model to classify samples comparable to sensory assessment. 22 batches of the same beer brand were assessed for sensory and chemically described with the contents of alcohols and esters (9),hop essential oils compounds (15) by GC and other aroma volatiles (33), analysed by head space SPME-GC/MS. The best matchings of 91 % regarding samples classification on the base of chemical analyses to sensory scores were achieved with a data set of results from HS-SPME and higher alcohols and esters analyses by RDA. Results shows that deviations in beer aroma are not a consequence of a permanent repeatable error in brewing process and are not influenced by raw materials but are the consequences of the alcoholic fermentation. The sensory analysis could be replaced with chemical/statistical analysis on an appropriate data set and for a distinct beer brand. Good results confirm our approach, however for different beer brands or types, this method should me optimised.
COBISS.SI-ID: 910455