Search

The state of Florida ranks third in the United States in beer production by volume, yet does not boast a commercially viable barley crop. This presents a potential market for Florida-grown barley. Despite similarities between the USDA Plant Hardiness Zones of Florida and traditional barley-growing regions, there persists a lack of best management practices for the successful cultivation and establishment of a barley crop in Florida. The purpose of this study was to investigate the potential viability of eight spring-type barley varieties grown in Florida by comparing crop yields, extract, fermentability, and volatile compounds. Barley is not a typical crop grown in Florida, however, the inclusion would provide welcome diversification options for Florida farmers to grow over winter. This study is an initial investigation into the use of Florida barley as an ingredient in beer production. The average yields of the eight varieties ranged from 31.5 ± 6.8 to 42.9 ± 11.8 bushels per acre (1,695–2,308 kg/ha) for the optimal planting dates, which are comparable to similar growing regions. Fine Grind (f.g.) extract concentrations were highest in Copeland, Esma, Pinnacle, and Opera barley varieties, ranging from 68.4 to 73.6% dry basis (d.b.). Concerning fermentability, Copeland and Esma had the lowest final attenuation among the Florida-grown barleys (1.51 and 1.92°P, respectively). There were minor differences in volatile compounds between the control and experimental barleys. The results of this study support the possible viability of Florida-grown barley for brewing applications that prioritize using local ingredients. [ABSTRACT FROM AUTHOR]

Why was the work done: Diastatic variants of Saccharomyces cerevisiae are unusual in producing an extracellular glucoamylase which enables the breakdown of starch to fermentable sugars. Diastatic S. cerevisiae has long been viewed negatively as a contaminant of especially beer packaged in cans or bottles. However, this view is being reconsidered due to the opportunities that diastatic strains present for niche fermented products and distillation applications. What are the main findings: This review highlights the utilisation of diastatic S. cerevisiae for its flavour potential, and processing applications in the brewing, distilling, and biofuel industries. Further, genetic differences are compared with non-diastatic strains of S. cerevisiae, together with commonly employed and emerging methods of detection. Why is the work important: Diastatic yeast strains can be used to create flavour profiles that resemble traditional beverages and can be used to achieve fermentation with higher attenuation. This offers greater fermentation efficiency in, for example, the development of low-calorie beers. Additionally, the ability of diastatic strains of S. cerevisiae to convert non-fermentable oligosaccharides to fermentable sugars enables applications that range from novel beverages using unusual raw materials to more efficient distillation and biofuel production. The negative attributes that are associated with diastatic S. cerevisiae yeasts can be managed through co-inoculation or hybridisation with standard strains. [ABSTRACT FROM AUTHOR]

Belgian Saisons and Lambics are two well‐known examples in the brewing industry of mixed fermentations, combination of two or more yeast and/or bacteria strains. The purpose of this study was to determine the impact different pitch rates of Saccharomyces cerevisiae (traditional brewing yeast) and S. cerevisiae var. diastaticus (a variant associated with Belgian styles) had on the fermentation kinetics and concentration of the volatile compounds in the finished beers. A series of brews were performed utilizing ratios of S. cerevisiae and diastaticus. The fermentations were heavily monitored, and a model was used to fit fermentation variables. It was found that mixed fermentations produced behaviors that were predictable and proportional to the mixture ratios. As expected, the pure cultural fermentations of diastaticus had a slower fermentation midpoint (M) at 45.45 h versus 28.28 h for S. cerevisiae with the mixed ones falling in between the two. Flavor and aroma play a key role in the acceptability of beer. The mixed fermentations showed a combination of the two different yeast strains aromatic profiles. When combined, there was a strong linearity between alcohols (R2 = 0.94), esters (R2 = 0.89), and the overall total (R2 = 0.91) volatile compounds. Practical Application: Modeling is a widely utilized tool in several different fields. The purpose of this research is to apply modeling techniques to describe the fermentation speed and flavor profile of a mixed fermentation between S. cerevisiae and diastaticus. The equations from this data can be used by brewers for product development purposes to make beers with certain flavor profiles within a desired timeframe. [ABSTRACT FROM AUTHOR]

This research aimed to assess how the partial removal of carbon dioxide affects fermentations to provide a better understanding of how the manipulation of carbon dioxide concentration can be used to optimize industrial fermentations. To achieve this, fermentation kinetics, fermentation metabolic products, and yeast stress indicators were analyzed throughout ongoing brewing fermentations conducted under partial vacuum with atmospheric pressure controls. The partial vacuum reduced the solubility of carbon dioxide in the media and decreased the time necessary to reach carbon dioxide saturation. The effect was an increased rate of fermentation, and significantly more viable cells produced under vacuum pressure compared to controls. Ethanol, glycerol, and volatile organic compound concentrations were all significantly increased under partial vacuum, while indicators of yeast stress (trehalose) were reduced. Additionally, as the number of yeast cells was higher under partial vacuum, less sugar was consumed per volume of yeast cell. This study measured fermentation kinetics, metabolic products, and yeast health to holistically assess the effect of partial vacuum during a batch fermentation and found significant differences in each that can be individually exploited by researchers and industry. Summary An exploration of batch yeast fermentation in a low-pressure environment, with a focus on the health and productivity of the yeast cells. [ABSTRACT FROM AUTHOR]

Recently there has been an increased interest in characterising the rates of alcoholic fermentations. Sigmoidal models have been used to predict changes such as the rate of density decline. In this study, three published sigmoidal models were assessed and fit to industrial fermentation data. The first is the four-parameter logistic model described in the ASBC Yeast-14 method. The second model is a nested form of the four-parameter logistic function, adding an extra parameter, creating the 5-parameter logistic equation., where an additional parameter was added to allow for asymmetry. The final model is a three-parameter logistic equation which describes the change in the Apparent Degree of Fermentation with time. The three models were compared by fitting them to industrial data from Australian and Canadian lagers, American and Scottish ales and Scotch Whisky fermentations. The model fits were then compared to one another with a technique developed by Akaike and a nested F-test. The Akaike information criterion compares the models and accounts for both the goodness of fit, and the number of parameters in the model. Finally, consideration was given to the establishment of prediction bands (that enclose the area that one can be 99% sure contains the true datapoints). Calculation of these bands was "challenging" but successful as the industrial fermentation data was heteroscedastic. [ABSTRACT FROM AUTHOR]