Production Of Low-alcohol Beers Research Articles

The Influence of Different Non-Conventional Yeasts on the Odour-Active Compounds of Produced Beers

The interest in new beer products, which has been growing for several years, forces technologists and brewers to look for innovative raw materials, such as hops, new sources of carbohydrates or yeast. The aim of the presented study was to evaluate the effect of selected Saccharomyces (Saccharomyces paradoxus (CBS 7302), S. kudriavzevii (CBS 3774), S. cerevisiae (Safbrew T-58)) and non-Saccharomyces yeast (W. anomalus (CBS 5759), Ha. uvarum (CBS 2768), D. bruxellensis (CBS 3429), Z. bailii (CBS 749), and T. delbrueckii (D10)) on the fermentation process, basic parameters and odour-active compounds of the produced beers. The chemical composition and key aroma components of the obtained beers were determined using various chromatographic methods (HPLC, GC-FID, GC-MS, and GC-O). We showed large differences between the key aroma components depending on the culture of microorganisms used. Forty different compounds that have an active impact on the creation of the aroma of beers were detected, among which the most important are: β-phenylethanol, ethyl hexanoate, ethyl 4-methylpentanoate, ethyl dihydrocinnamate and β-damascenone. We also found the presence of components specific to the yeast strain used, such as 2-methoxy-4-vinylphenol, γ-decalactone, methional, nerolidol and others. Among the analyzed yeasts, S. kudriavzevii and W. anomalus should be distinguished, which produced beers with intense fruity and floral aromas and were also characterized by favorable features for brewing. The Z. bailii strain also turned out to be interesting as a potential starter culture for the production of low-alcohol beers, significantly differing in sensory characteristics from the standard ones.

Exploiting Non-Conventional Yeasts for Low-Alcohol Beer Production

Non-Saccharomyces yeasts represent a very appealing alternative to producing beers with zero or low ethanol content. The current study explores the potential of seven non-Saccharomyces yeasts to produce low-alcohol or non-alcoholic beer, in addition to engineered/selected Saccharomyces yeasts for low-alcohol production. The yeasts were first screened for their sugar consumption and ethanol production profiles, leading to the selection of strains with absent or inefficient maltose consumption and consequently with low-to-null ethanol production. The selected yeasts were then used in larger-scale fermentations for volatile and sensory evaluation. Overall, the yeasts produced beers with ethanol concentrations below 1.2% in which fusel alcohols and esters were also detected, making them eligible to produce low-alcohol beers. Among the lager beers produced in this study, beers produced using Saccharomyces yeast demonstrated a higher acceptance by taster panelists. This study demonstrates the suitability of non-conventional yeasts for producing low-alcohol or non-alcoholic beers and opens perspectives for the development of non-conventional beers.

Impact of Non-Saccharomyces Wine Yeast Strains on Improving Healthy Characteristics and the Sensory Profile of Beer in Sequential Fermentation.

The use of non-Saccharomyces yeasts in brewing is a useful tool for developing new products to meet the growing consumer demand for innovative products. Non-Saccharomyces yeasts can be used both in single and in mixed fermentations with Saccharomyces cerevisiae, as they are able to improve the sensory profile of beers, and they can be used to obtain functional beers (with a low ethanol content and melatonin production). The aim of this study was to evaluate this capacity in eight non-Saccharomyces strains isolated from Madrid agriculture. For this purpose, single fermentations were carried out with non-Saccharomyces strains and sequential fermentations with non-Saccharomyces and the commercial strain SafAle S-04. The Wickerhamomyces anomalus strain CLI 1028 was selected in pure culture for brewing beer with a low ethanol content (1.25% (v/v)) for its fruity and phenolic flavours and the absence of wort flavours. The best-evaluated strains in sequential fermentation were CLI 3 (Hanseniaspora vineae) and CLI 457 (Metschnikowia pulcherrima), due to their fruity notes as well as their superior bitterness, body, and balance. Volatile compounds and melatonin production were analysed by GC and HPLC, respectively. The beers were sensory-analysed by a trained panel. The results of the study show the potential of non-Saccharomyces strains in the production of low-alcohol beers, and as a flavour enhancement in sequential fermentation.

Repurposing brewery contaminant yeast as production strains for low-alcohol beer fermentation.

A number of fungal isolates were recently obtained from a survey of the microbiota of multiple breweries and brewery products. Here, we sought to explore whether any of these brewery contaminants could be repurposed for beneficial use in beer fermentations, with particular focus on low-alcohol beer. There were 56 yeast strains first screened for the utilization of different carbon sources, ability to ferment brewer's wort, and formation of desirable aroma compounds. A number of strains appeared maltose-negative and produced desirable aromas without obvious off-flavours. These were selected for further scaled-up wort fermentations. The selected strains efficiently reduced wort aldehydes during fermentation, thus eliminating undesirable wort-like off-flavours, and produced a diverse volatile aroma profile. Two strains, Trigonopsis cantarellii and Candida sojae, together with a commercial Saccharomycodes ludwigii reference strain, were selected for 30-L-scale wort fermentations based on aroma profile and similarity to a commercial reference beer during sensory analysis using projective mapping. Both strains performed comparably to the commercial reference, and the T.cantarellii strain in particular, produced low amounts of off-flavours and a significantly higher amount of the desirable monoterpene alcohol trans-geraniol. The strain was also sensitive to common food preservatives and antifungal compounds and unable to grow at 37°C, suggesting it is relatively easily controllable in the brewery, and appears to have low risk of pathogenicity. This study shows how the natural brewery microbiota can be exploited as a source of non-conventional yeasts for low-alcohol beer production.

Cold Mash in Brewing Process: Optimization of Innovative Method for Low-Alcohol Beer Production

Beer is described as a drink susceptible to changes, so any modification in the production process will cause variations in the sensory profile and chemical composition. Alcohol removal during low-...

Performance of Wild Non-Conventional Yeasts in Fermentation of Wort Based on Different Malt Extracts to Select Novel Starters for Low-Alcohol Beers

Nowadays, the increasing interest in new market demand for alcoholic beverages has stimulated the research on useful strategies to reduce the ethanol content in beer. In this context, the use of non-Saccharomyces yeasts to produce low-alcohol or alcohol-free beer may provide an innovative approach for the beer market. In our study, four wild non-Saccharomyces yeasts, belonging to Torulaspora delbrueckii, Candida zemplinina and Zygosaccharomyces bailii species, were tested in mixed fermentation with a wild selected Saccharomyces cerevisiae strain as starters for fermentation of different commercial substrates used for production of different beer styles (Pilsner, Weizen and Amber) to evaluate the influence of the fermentative medium on starter behaviour. The results obtained showed the influence of non-Saccharomyces strains on the ethanol content and organoleptic quality of the final beers and a significant wort–starter interaction. In particular, each starter showed a different sugar utilization rate in each substrate, in consequence of uptake efficiency correlated to the strain-specific metabolic pathway and substrate composition. The most suitable mixed starter was P4-CZ3 (S. cerevisiae–C. zemplinina), which is a promising starter for the production of low-alcohol beers with pleasant organoleptic characteristics in all the tested fermentation media.

Investigation of mashing regimes for low-alcohol beer production

Investigation of mashing regimes for low-alcohol beer production

Screening of new strains ofSaccharomycodes ludwigiiandZygosaccharomyces rouxiito produce low-alcohol beer

Low-alcohol beer (0.5–1.2% v/v ethanol) is a less common brewing industry output than standard beer but there is an increasing interest in this product, as evidenced by increased attention to health and safety and government policies on alcohol and diet. The main challenge in the production of low-alcohol beer is the achievement of a product as similar as possible to regular beer, particularly concerning the content of the volatile compounds. These compounds can be lost during the physical removal of alcohol by dialysis, reverse osmosis and vacuum rectification. Consequently, an alternative technique is the use of biological methods, which involve the employment of non-conventional yeasts. In this paper, 11 non-conventional yeast strains were tested for low-alcohol beer production. The strains used belonged to two different species: Saccharomycodes ludwigii and Zygosaccharomyces rouxii. The beer samples produced by these strains were analysed for their ethanol content and main volatile compounds. The S. ludwigii strains were more suitable for brewing low-alcohol beer, especially strain DBVPG 3010, which also showed a higher content of esters and a lower amount of diacetyl compared with previous reports. The Z. rouxii strains produced an ethanol and diacetyl content above the taste threshold. This screening project can be considered as a first step towards the production of low-alcohol beer by means of new selected non-conventional yeasts. Copyright © 2015 The Institute of Brewing & Distilling

Pilot Plant Production of Low-Alcohol Beer by Osmotic Distillation

Osmotic distillation (OD) is a membrane technology frequently applied for dissolved gas removal from liquids and for liquid concentration; recently, there has been increasing interest in the use of this technology to dealcoholize beverages. The aim of this work was to ascertain the feasibility of a semi-industrial scale of beer dealcoholization by OD using a pilot plant. The process was optimized by the variation of technological parameters to determine the effect of different operating conditions on the quality and organoleptic properties of the dealcoholized beer. The most important beer quality parameters were determined before and after the dealcoholization, as well as the volatile composition by gas chromatography and the organoleptic characteristics by a trained panel. The findings indicated that OD is an appropriate process for low-alcohol beer production. Some issues, such as the loss of volatile compounds and the high amount of stripping solution required, limit its growth. The report of the panel showed that beer with an organoleptic profile more characterized by malty features than by ester content could be appropriate for this treatment.

Effects of Operating Conditions during Low-Alcohol Beer Production by Osmotic Distillation

Osmotic distillation (OD) is a membrane technology most commonly used for liquid concentration, but recently there has been an increased interest in ethanol removal from alcoholic beverages. The aim of this paper is to investigate the effect of the variation of some operating conditions (temperature, flow rate, type and amount of stripping solution), specifically in regard to the effect on quality and sensory properties of the dealcoholized beers. The results indicated that temperature and flow rate variation showed no significant effect, whereas stripping solution variation had substantial effects mainly in terms of the ethanol removed. A cost appraisal showed that the operating costs were high mainly because of the cost of the stripping water. However, it is important to consider the final stripping solution, which is slightly alcoholic and enriched in flavor. For this reason, it could be reused in the manufacture of beverages, for instance as high gravity beer dilution water.

Immobilized cell technology in beer brewing: Current experience and results

Immobilized cell technology (ICT) has been attracting continual attention in the brewing industry over the past 30 years. Some of the reasons are: faster fermentation rates and increased volumetric productivity, compared to those of traditional beer production based on freely suspended cells, as well as the possibility of continuous operation. Nowadays, ICT technology is well established in secondary fermentation and alcohol- free and low-alcohol beer production. In main fermentation, the situation is more complex and this process is still under scrutiny on both the lab and pilot levels. The paper outlines the most important ICT processes developed for beer brewing and provides an overview of carrier materials, bioreactor design and examples of their industrial applications, as well as some recent results obtained by our research group. We investigated the possible applications of polyvinyl alcohol in the form of LentiKats?, as a potential porous matrices carrier for beer fermentation. Given are the results of growth studies of immobilized brewer's yeast Saccharomyces uvarum and the kinetic parameters obtained by using alginate microbeads with immobilized yeast cells and suspension of yeast cells as controls. The results indicate that the immobilization procedure in LentiKat? carriers has a negligible effect on cell viability and growth. The apparent specific growth rate of cells released in medium was comparable to that of freely suspended cells, implying preserved cell vitality. A series of batch fermentations performed in shaken flasks and an air-lift bioreactor indicated that the immobilized cells retained high fermentation activity. The full attenuation in green beer was reached after 48 hours in shaken flasks and less than 24 hours of fermentation in gas-lift bioreactors.

NEW DEVELOPMENTS IN THE BREWING INDUSTRY USING IMMOBILISED YEAST CELL BIOREACTOR SYSTEMS*

The use of immobilised yeast cell systems in industry has been extensively reported in the literature. The brewing industry is closely examining immobilisation technology and evaluating its merits. Various immobilisation methods are available to researchers and the nature of the application often dictates the choice of an immobilisation matrix. Industrial scale systems utilising immobilised yeast cells adsorbed to pre-formed carriers have been used for the production of low alcohol beers and for maturation or secondary fermentation of beer. Research relating to the primary fermentation of beer continues and several groups have developed laboratory scale systems. An overview of the respective technologies is provided and several relevant industrial applications cited.

Influence of beer flow rate on mass transfer kinetics in beer dialysis

The basic parameters for mass transfer of alcohol and extract have been determined. The beer flow rate influences both efficiency and selectivity of the alcohol separation. The results suggest that, in order to achieve a satisfactory selectivity in the alcohol free- and low-alcohol beer production, using dialysers with hollow fibre Cuprophan membranes, the beer flow rate should not be less than 500 ml min−1 m−2.

ESTER FORMATION IN BREWERY FERMENTATIONS

Esters are secondary products produced by brewing yeasts during the anaerobic metabolism of sugars and constitute one of the largest and most important groups of compounds affecting beer flavour. Many esters can be formed, the most important being ethyl acetate, isoamyl acetate, isobutyl acetate, 2-phenylethyl acetate and ethyl hexanoate. The odour threshold levels for ester detection are very low. Esters are especially important in high gravity brewing, where over production occurs causing unwanted solvent-like flavours. They are also important in low alcohol beer production due to the low levels produced, which can result in beers with little flavour. The factors influencing ester production are reviewed, together with the ways in which they can be used to control ester synthesis. It is believed that acetate esters are synthesized by an enzyme called alcohol acetyl transferase (AAT) which uses as substrates an alcohol and acetyl co-enzyme A; the latter plays a central role in many intracellular reactions. However, esters can also be synthesized by esterase enzymes working in reverse. Several attempts have been made to locate the AAT enzyme and recent work suggests that it is located in either the yeast cell plasma membrane or in intracellular organelles called “vacuomes”.