Pre-fermentation of malt whisky wort using Lactobacillus plantarum and its influence on new-make spirit character

Reid, Struan; Speers, R. Alex; Willoughby, Nicholas; Lumsden, William B.; Maskell, Dawn Louise

doi:10.1016/j.foodchem.2020.126605

Cited by 15 publications

(12 citation statements)

References 43 publications

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“…The few esters that increased belonged to the group of fatty acid ethyl esters. The decrease in esters and higher alcohols was an unexpected result because the presence of lactic acid bacteria in whisky is often connected to higher acid and ester concentrations [2][3][4][5][6][7]18,23,49,50]. Nevertheless, less turbid worts are linked to a reduction in fatty acids [51], which are needed for ester production and explains their low concentration.…”

Section: Wort Stage Advantages Disadvantagesmentioning

confidence: 99%

“…The inherent microflora of the distillery, the malt, and the (frequently wooden) washbacks (fermentation vessels) are important for flavour development in Scotch whisky. In particular, lactic acid bacteria are involved in converting higher alcohols to acetate esters after alcoholic fermentation by the yeast, Saccharomyces cerevisiae [2][3][4][5][6][7][8]. Additionally, by not heat-treating the wort, the enzymes that breakdown the starch (α-amylase, β-amylase, limit dextrinase, α-glucosidase) stay active during the fermentation [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Varieties in batch or day variations, such as wort gravity, free amino nitrogen (FAN), or indigenous microorganisms, can significantly influence the fermentation and overshadow other factors researched, such as the fermentation conditions or yeast strains. To date, researchers have used three different approaches to acquire malt: producing wort in the lab with a nanobrewery; following standard brewing protocols, such as EBC methods [4,11,12,19,22,[24][25][26][27][28]; or obtaining a large batch of wort from a local distillery and freezing it [29][30][31]. Nevertheless, for all three approaches, enough wort from the same batch must be obtained before starting a study, and this makes extending experiments nearly impossible.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Whisky Fermentations: Influence of Wort Pretreatments

Daute

Jack

Harrison

et al. 2021

Foods

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In addition to ethanol yield, the production of flavour congeners during fermentation is a major consideration for Scotch whisky producers. Experimental whisky fermentations can provide useful information to the industry, and this is the focus of this paper. This study investigated the impact of wort pretreatments (boiled, autoclaved, filtered) on fermentation performance and flavour development in Scotch whisky distillates as an alternative to freezing wort for storage. Our study showed that no significant sensorial differences were detected in low wines (first distillates), while the chemical compositions showed clear changes in increased levels of esters and higher alcohols in boiled and autoclaved wort. In contrast, filtered wort comprised overall lower levels of congeners. Regarding alcohol yield, all three pretreatments resulted in decreased yields. In practice, the pretreatment of wort prior to fermentation requires additional process operations, while freezing requires large storage units. The pretreatments adopted in this study significantly influence the composition of the malt wort used for experimental whisky fermentations, and this results in a poorer fermentation performance compared with untreated wort. We recommend the use of fresh or frozen wort as the best options for small-scale fermentation trials.

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Section: Wort Stage Advantages Disadvantagesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Whisky Fermentations: Influence of Wort Pretreatments

Daute

Jack

Harrison

et al. 2021

Foods

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“…Non-sterile fermentations, such as in whisky production, require fast fermenting strains with high temperature and high ethanol tolerance. The presence of bacterial strains is tolerated and may be associated with positive aroma contribution [ 14 , 15 ]. The limitations of the use of Saccharomyces in fermentations, compared to some successful spontaneous fermentations that are based on a much broader biodiversity, have led to an interest in employing NCYs in beverage productions.…”

Section: Introductionmentioning

confidence: 99%

Co-Fermentations of Kveik with Non-Conventional Yeasts for Targeted Aroma Modulation

et al. 2022

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Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high fermentation rate, thermotolerance, lack of phenolic off flavor production (POF-) and strong flocculation phenotype. In this study, we used five single cell yeast isolates from different Kveik yeasts, analyzed their fermentation and flavor production, and compared it with a typical yeast used in distilleries using 20 °C and 28 °C as the fermentation temperatures. One of the isolates, Kveik No 3, showed an impairment of maltotriose utilization and thus a reduced ethanol yield. Kveik fermentations for spirit production often harbor bacteria for flavor enrichment. We sought to improve Kveik fermentations with non-conventional yeasts (NCY). To this end we co-fermented Kveik isolates with Hanseniaspora uvarum, Meyerozyma guilliermondii and Pichia kudriavzevii using 5:1 ratios (Kveik vs. NCY) at 20 °C. The combinations of Kveik No 1 with P. kudriavzevii and Kveik No 1 with Hanseniaspora uvarum showed substantially increased amounts of specific volatile aroma compounds that were previously identified in the NCYs. Our results indicate that Kveik isolates appear to be suitable for co-fermentations with certain NCY to enhance beer or spirit fermentations, increasing the potential of these yeasts for beverage productions.

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“…However, due to equipment costs and the need for trained personnel, it is not a standard method, generally only being used in larger laboratories. GC-MS is also used for research purposes, often in combination with sensory techniques [34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Three Approaches to Assess the Flavour Characteristics of Scotch Whisky Spirit

et al. 2021

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This study compared the use of three sensory and analytical techniques: Quantitative Descriptive Analysis (QDA), Napping, and Gas Chromatography-Mass Spectrometry (GC-MS) for the assessment of flavour in nine unmatured whisky spirits produced using different yeasts. Hierarchical Multiple Factor Analysis (HMFA) showed a similar pattern of sample discrimination (RV scores: 0.895–0.927) across the techniques: spirits were mostly separated by their Alcohol by Volume (ABV). Low ABV spirits tended to have heavier flavour characteristics (feinty, cereal, sour, oily, sulphury) than high ABV spirits, which were lighter in character (fruity, sweet, floral, solventy, soapy). QDA differentiated best between low ABV spirits and GC-MS between high ABV spirits, with Napping having the lowest resolution. QDA was time-consuming but provided quantitative flavour profiles of each spirit that could be readily compared. Napping, although quicker, gave an overview of the flavour differences of the spirits, while GC-MS provided semi-quantitative ratios of 96 flavour compounds for differentiating between spirits. Ester, arenes and certain alcohols were found in higher concentrations in high ABV spirits and other alcohols and aldehydes in low ABV spirits. The most comprehensive insights on spirit flavour differences produced by different yeast strains are obtained through the application of a combination of approaches.

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Pre-fermentation of malt whisky wort using Lactobacillus plantarum and its influence on new-make spirit character

Cited by 15 publications

References 43 publications

Experimental Whisky Fermentations: Influence of Wort Pretreatments

Experimental Whisky Fermentations: Influence of Wort Pretreatments

Co-Fermentations of Kveik with Non-Conventional Yeasts for Targeted Aroma Modulation

Comparison of Three Approaches to Assess the Flavour Characteristics of Scotch Whisky Spirit

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