Yeast management and high gravity fermentation

Debourg, A.

doi:10.1016/j.cervis.2010.05.001

Cited by 9 publications

(8 citation statements)

References 2 publications

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“…In our studies, the increase in the dose of the yeast from 5 to 9 million cells/mL increased the speed of the process, expressed as a daily drop in the extract from 1.45 to 1.95°P. Debourg believes that the selection of the correct dose of yeast is an essential treatment technology in order to obtain constant and reproducible fermentation parameters and stable yeast vitality.…”

Section: Resultsmentioning

confidence: 71%

The effect of pitching rate on fermentation, maturation and flavour compounds of beer produced on an industrial scale

Kucharczyk

Tuszyński

2015

J. Inst. Brew.

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The aim of the study was to determine the effect of the initial number of yeast cells in the wort on the process of fermentation, maturation and the content of the volatile components of beer, as well as the viability and vitality of the yeast biomass. The experiments were performed on an industrial scale, with fermentation and maturation in cylindro-conical fermentation tanks with a capacity of 3800 hL. Yeast for pitching was collected after secondary fermentation (third passage) and wort pitching levels were 5 × 10 6 , 7 × 10 6 and 9 × 10 6 cells/mL. During fermentation and maturation, the changes in the content of the extract, yeast growth, yeast vitality and selected volatile components were investigated. Experiments showed that the yeast inoculum had a significant impact on the course of the fermentation and metabolic changes. With increasing numbers of cells introduced into the wort, the content of the esters and fusel alcohols increased, while the acetaldehyde concentration decreased. These changes affected the final quality of the beer.

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Section: Resultsmentioning

confidence: 71%

The effect of pitching rate on fermentation, maturation and flavour compounds of beer produced on an industrial scale

Kucharczyk

Tuszyński

2015

J. Inst. Brew.

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“…Moreover, oxygen is relatively poorly soluble in mashes that contain increased amounts of solids. Debourg [18] illustrated that the use of yeast pre-oxygenation prior to pitching and the control of pitching rate are essential prerequisites for consistent and predictable VHG fermentation performances.…”

Section: Evect Of Nutrient Supplementationmentioning

confidence: 99%

“…Moreover, a combination of HG brewing with other modern practices, such as the use of tall cylindroconical fermentors, results in increased hydrostatic pressure, carbon dioxide level, and decreased oxygen level, as well. Many authors have suggested various methods to overcome these drawbacks such as higher fermentation temperature, nutritional supplementation [14,15,24,54], mutant yeast strain [9], more eYcient aeration than conventional brewing [15,18], higher pitching rate [25,45,70] and immobilized yeast [46,47,51,66,83].…”

Section: Vhg Brewingmentioning

confidence: 99%

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

Puligundla

Šmogrovičová

Obulam

et al. 2011

J Ind Microbiol Biotechnol

177

109

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There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized.

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“…Debourg (2010) uvádí jako ideální podmínky skladování kvasnic při teplotě 1 °C, se zahrnutím kroku uvolnění CO 2 ze skladovacích nádob. Naopak ve studii autorského kolektivu Somani et al (2012) nebyly u kmene S. pastorianus W34/70 pozorová-ny rozdíly ve viabilitě, obsahu glykogenu a trehalosy u kvasnic uchovávaných anaerobně "pod pivem" při teplotě 4 a 10 °C.…”

Section: Teplota Skladováníunclassified

“…According to Debourg (2010) optimal yeast storage conditions are at 1 °C with the inclusion of a step allowing the release of CO 2 from the storage containers. On the other hand, Somani et al (2012) did not observed any differences in viability and the content of glycogen and trehalose in S. pastorianus W34/70 yeast strain kept anaerobically "under beer" at 4 °C and 10 °C.…”

Section: Storage Temperaturementioning

confidence: 99%