Optimisation of lab-scale continuous alcohol-free beer production

Abstract

Lehnert R., Novák P., Macieira F., Kuřec M., Teixeira J.A., Branyik T. (2009): Optimisation of labscale continuous alcohol-free beer production. Czech J. Food Sci., 27: 267-275.In order to study the formation and conversion of the most important flavour compounds, the real wort used in alcohol-free beer fermentation was mimicked by a complex model medium containing glucose, yeast extract, and selected aldehydes. The fermentation experiments were carried out in a continuously operating gas-lift reactor with brewing yeast immobilised on spent grains (brewing by-product). During the continuous experiment, parameters such as oxygen supply, residence time (Rt), and temperature (T) were varied to find the optimal conditions for the alcohol-free beer production. The formation of ethanol, higher alcohols (HA), esters (ES), as well as the reduction of aldehydes and consumption of glucose were observed. The results suggest that the process parameters represent a powerful tool in controlling the degree of fermentation and flavour formation brought about by immobilised biocatalyst. Subsequently, the optimised process parameters were used to produce real alcohol-free beer during continuous fermentation. The final product was compared with batch fermented alcohol-free beers using the methods of instrumental and sensorial analysis.

Simulation and flavor compound analysis of dealcoholized beer via one-step vacuum distillation

“…The profile of quantified volatiles consisted of 5 alcohols (1-propanol, 2-methylpropanol, 2-methylbutanol, 3-methylbutanol and 2-phenylethanol) and 2 esters (ethyl acetate and isoamyl acetate). These compounds are considered as ones of the main alcohols and esters in beer Lehnert et al, 2009;Rodrigues, Caldeira, & Câmara, 2008;Willaert & Nedovic, 2006), the most abundant being ethyl acetate, isoamyl acetate, the amyl alcohols and isobutanol (Piddocke, Kreisz, Heldt-Hansen, Fog Nielsen, & Olsson, 2009). Also, these compounds are those currently analyzed by other authors because they are relevant flavor compounds in beer (Charry-Parra, DeJesús-Echevarria, & Perez, 2011;Kobayashi, Shimizu, & Shioya, 2008) and chosen as reference compounds when studying industrial processes for production of non-alcoholic beers (Catarino & Mendes, 2011;Mota et al, 2011).…”

“…The aroma profile is clearly damaged and other, less pleasant flavors, like bready, worty or caramel notes can appear Catarino et al, 2009;Lehnert et al, 2009;Sohrabvandi et al, 2010). To compensate these disadvantages many breweries use a modified brewing technology for the production of a more aromatic original beer.…”

Volatile Compound Profiling in Commercial Lager Regular Beers and Derived Alcohol-Free Beers After Dealcoholization by Vacuum Distillation

“…High losses of volatile compounds have been reported during the lab-scale vacuum dealcoholization process and also when commercial regular beers and their related nonalcoholic beers were compared (Zürcher et al 2005;Montanari et al 2009;Lehnert et al 2009;Brányik et al 2012;Strejc et al 2013). In this study, the major losses were found over the initial period of the dealcoholization experiments, and, hence, although the system is only nearly comparable to the industrial scale ones, our results suggest that the volatile compound behavior is likely to be also comparable.…”

“…In this study, the major losses were found over the initial period of the dealcoholization experiments, and, hence, although the system is only nearly comparable to the industrial scale ones, our results suggest that the volatile compound behavior is likely to be also comparable. For this reason, we suggest that in thermal dealcoholization at industrial scale, some additional system to recover the aroma compounds should be implemented for further improvement of the organoleptic characteristics of the final product by adding them to it (Zürcher et al 2005;Lehnert et al 2009;Mota et al 2011). This could be achieved by separating the ethanol from the key compounds with processes such as pervaporation or by addition of appropriate amounts of the key flavor compounds to the final dealcoholized beer (Olmo et al 2014).…”

Toxicology and the biological role of methanol and ethanol: Current view

“…However, the content of ethanol in beverages can be different in disparate countries and regions. In the Czech Republic, for example, the typical content of ethanol in beers is 3-4%, respectively 4-5% (beer strength 10°, respectively 12°) and 10 -13% v/v for wines [15][16][17][18] . Fermented alcoholic beverages are mainly produced using the yeast Saccharomyces cerevisiae, S. eubayanus and S. pastorianus (formerly S. carlsbergensis), but other yeasts such as Kluyveromyces sp.…”