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Bottle-fermented sparkling wine producers are continuously striving to increase quality and produceniche products. One production tool that could be used is a cork closure instead of a crown cap closureduring the second fermentation and maturation on yeast lees. Anecdotal evidence suggests that thisleads to stylistic differences in the wine. Six pairs of South African bottle-fermented sparkling wines(Méthode Cap Classique), closed by either a cork or crown cap, were investigated. Analyses includedbottle pressure, infrared spectroscopy, phenolic acids, sensory attributes and CO2 kinetics. Generally,there were differences between the cork-closed and crown-capped wines. Cork-closed wines tended tohave lower pressure compared to crown-capped wines, albeit still well within legal requirements. Otherdifferences were evident in the infrared spectral data and in the polyphenol profile of the analysed wines.Levels of gallic, caftaric, caffeic and p-coumaric acids could be used collectively as marker compounds todifferentiate between cork-closed and crown-capped wines. The effect of the cork was also evident in thesensory attributes and CO2 kinetics. Cork-closed wines were judged to have smaller bubbles and a longeraftertaste. It was also shown that the cork-closed wines tended to lose CO2 from the glass slower after beingpoured than their crown-capped counterparts. The data tentatively support the anecdotal evidence thatcork can be used during the second fermentation and maturation on the yeast lees to change the style ofbottle-fermented sparkling wine.

Bottle fermented sparkling wine in South Africa is known as Méthode Cap Classique which is based on the method used in France for Champagne. The use of cork, instead of a crown cap during the second fermentation in sparkling wine was investigated for its effect on the phenolic profile of wines. Phenolic acids susceptible to migration from cork into wine were studied in two-disc corks from three different commercial suppliers, coded as Cork A, Cork R and Cork C and a crown cap closure. Gallic, caftaric, caffeic and p-coumaric acids were quantified in all samples using a liquid chromatographic technique. Physicochemical parameters were also measured in the wine using a spectrophotometric technique. Total acidity and pH were not significantly different among the wines. Cork R wines were however significantly different in alcohol. Residual sugar for all samples was below the limit of detection. Gallic acid was significantly highest in Cork A wines, which indicates the contribution of Cork A to the concentration of this compound in the wine. Different cork types are assumed to release different concentrations of phenolic compounds. This may be due to differences in surface roughness of cork that would increase the surface area in contact with the wine. Therefore, corks from different origins (suppliers) could be used to bring about subtle differences to the wine.

Background The Kei apple is a tree found on the African continent. Limited information exists on the effect of alcoholic and acetous fermentation on the phytochemicals of Kei apple. The fruit has increased concentrations of l-malic, ascorbic, and phenolic acids among other compounds. Juice was co-inoculated with Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) to induce alcoholic fermentation (AF). Acetous fermentation followed AF, using an acetic acid bacteria (AAB) consortium. Results Saccharomyces cerevisiae + Sp wines and vinegars had the highest pH. Total acidity, soluble solids and l-malic acid decreased during AF and acetous fermentation, and was highest in Sc wines and vinegars. Volatile acidity (VA) concentration was highest in Sp vinegars but was not significantly different from Sc and Sc + Sp vinegars. Gallic acid was highest in Sp wines and vinegars, whereas syringic acid was highest in Sc wines and vinegars. The Sc + Sp wines were highest in caffeic, p-coumaric, and protocatechuic acids. Schizosaccharomyces pombe vinegars were highest in caffeic and p-coumaric acids. Highest concentrations of ferulic and sinapic acids were found in Sp and Sc wines, respectively. Chlorogenic acid was most abundant phenolic acid in both wines and vinegars. Conclusion Saccharomyces cerevisiae + Sp and Sc fermentation had a positive effect on most phenolic acids; Sc + AAB had an increased effect on syringic and chlorogenic acids, whereas Sp + AAB resulted in an increase in gallic, caffeic, and p-coumaric acids. The AAB selected had minimal performance with respect to VA production in comparison to commercial vinegars. Acetic acid bacteria selection for acetous fermentation should therefore be reconsidered and the decrease of certain phenolic acids during acetous fermentation needs to be investigated. © 2021 Society of Chemical Industry.

Grapes and wine contain phenolics divided into non-flavonoid and flavonoid classes. Yeast modulates the phenolics of wine by adsorption onto yeast cell walls. This may be advantageous for colour and quality. The effect of Torulaspora delbrueckii (654M2/1) and Saccharomyces cerevisiae (VIN13) on phenolics and sensory attributes of Cabernet Franc wines (2012/2013) were evaluated. Spectrophotometric analysis was used to determine the phenolic content. Sensory analysis was conducted by expert tasters to evaluate the wines. ANOVA showed that polyphenols and anthocyanins were higher in M2/1 + VIN13 wines (2012/2013) than 654 + VIN13 wines. Colour, fruitiness, mouthfeel, sweetness, astringency and quality were different between treatments. 654 + VIN13 wines (2012) were higher in polyphenols, acidity, astringency and mouthfeel than M2/1 + VIN13 wines. M2/1 + VIN13 (2012/2013) had increased colour and quality than 654 + VIN13 wines. Two treatments were identified for Cabernet Franc wines; M2/1 + VIN13 and 654 + VIN13, which resulted in wines with increased colour and wines with increased mouthfeel and astringency, respectively.

The non-Saccharomyces yeast Torulaspora delbrueckii contributes positively to the sensory properties of wines by affecting aroma and flavour due to changes in alcohols, esters, fatty acids and lactone levels. One of the less-studied aspects of T. delbrueckii is its effect on phenolic compounds relating to sensory attributes. An HPLC-DAD technique was used for the quantification of phenolic compounds in Chenin blanc wines made with S. cerevisiae and two T. delbrueckii yeasts over three vintages. Chemical and sensory data were subjected to ANOVA and PCA. VIN13, M2/1 and VIN13+M2/1 had a positive effect on the phenolic compound concentrations of Chenin blanc wines. Mouthfeel was highest in VIN13+654 wines and astringency highest in VIN13 wines. An association was evident between flavanols, astringency and mouthfeel for the VIN13, M2/1 and VIN13+M2/1 wines. Chenin blanc wines made with M2/1 and VIN13+M2/1 may result in increased phenolic compound concentrations and astringency, whereas 654 and VIN13+654 may result in wines with increased mouthfeel properties.

The aim of this study was to differentiate between wines of three diverse wine regions, namely the districts Paarl, Stellenbosch and Swartland, in the Western Cape on the basis of chemical parameters, namely pH, volatile acid, total acids, malic acid, lactic acid, glucose, fructose, ethanol and glycerol. A total of 140 young red wines (Pinotage, Cabernet Sauvignon and Merlot) obtained from the 2003 National Young Wine Show were analysed. Classification methods such as stepwise discriminant analysis, canonical discriminant analysis and linear discriminant analysis were applied to the data sets. A total classification of 34.04 % for Cabernet Sauvignon, 42.55 % for Pinotage and 31.25 % for Shiraz was determined. It was concluded that, under the conditions of this study, separation of the wines according to geographical regions was unsuccessful using the selected parameters.

The aim of this study was to differentiate between the geographic origins of wines produced in the Western Cape on the basis of their element composition. A total of 96 market-ready red and white wines (Pinotage, Shiraz, Merlot, Cabernet Sauvignon, Sauvignon blanc, Chardonnay and Chenin blanc) were analysed by means of inductively coupled plasma atomic emission spectrometry (ICP-AES). The discriminant methods: stepwise discriminant analysis, canonical discriminant analysis and linear discriminant analysis were applied to the data sets. A classification accuracy of 38% for Pinotage, 55% for Shiraz, 68% for Merlot, 75% for Cabernet Sauvignon, 93% for Sauvignon blanc, 68% for Chardonnay and 100% for Chenin blanc was achieved. Subject to the conditions of this study, it was concluded that differentiation between wines according to geographical origin was possible using the elemental composition.

Wine consumers predominantly use visual, sensory and textual descriptors as quality/preference indicators to describe olfactory sensations. In this study, different wines were analysed to generate relevant chemical and sensory characterisation data and attributes. Sequential inoculation of Syrah grape must was performed with a combination of Saccharomyces yeast, non-Saccharomyces yeasts and lactic acid bacteria for the possible improvement of Syrah wine quality. Selected anthocyanins, flavan-3-ols, flavonols and phenolic acids were quantified in Syrah wines using the reversed-phase high-performance liquid chromatography photodiode array detection (RP-HPLC-DAD) technique. Sensory (descriptive evaluation) and physicochemical/oenological parameters (Winescan® and OenoFoss™) results were compared to phenolic compound concentrations. Phenolic compound concentrations increased in Syrah wines made with a combination of a Saccharomyces reference yeast, non-Saccharomyces yeasts and lactic acid bacteria. Syrah wines made with a combination of Metschnikowia pulcherrima + Saccharomyces cerevisiae + Oenococcus oeni, and M. pulcherrima + S. cerevisiae + Lactobacillus plantarum, had higher flavonol concentrations compared to wines made without lactic acid bacteria. Syrah wines made with a combination of Saccharomyces cerevisiae (Sc) + Oenococcus oeni (LAB1) were highest in phenolic acid concentrations. Syrah wines made with a combination of M. pulcherrima + S. cerevisiae + L. plantarum had higher total anthocyanins than wines made without lactic acid bacteria. Syrah wine sensory attributes, viz. mouthfeel and astringency, correlated with a combination of lactic acid bacteria and yeast treatments. Syrah wines made with a combination of yeast and lactic acid bacteria (LAB) scored highest in overall quality. Indications are that the S. cerevisiae reference yeast retained more phenolic compounds during fermentation when compared to wines made with a combination of non-Saccharomyces yeasts and LAB. The improved red colour of Syrah wines may be achieved by sequential inoculation with non-Saccharomyces yeast and LAB. This could be beneficial where winemakers use grape cultivars with low anthocyanin levels in the grape skin to produce wines of improved quality.

Various factors affect the polyphenol compound concentrations of red grapes. These include cultivar, vineyard location, viticultural practices, microclimate, soil type and winemaking processes. Polyphenol compound concentrations of young and market-ready Cabernet Sauvignon, Pinotage and Shiraz wines were examined for the purpose of discrimination between grape cultivars. Thirty-five individual polyphenol compounds were quantified using a HPLC-DAD method. Stepwise discriminant analysis (SDA) was used to select a subset of discriminatory variables. In addition, data was grouped and investigated by canonical discriminant analysis, which showed that polyphenol concentrations can be used to discriminate among grape cultivars, young wines and market-ready wines. Flavonol, flavanol and anthocyanin patterns were used as a basis for differentiation of young wines, while flavanols and phenolic acids were used for differentiation of market-ready wines. Discriminant analysis performed at 95% significance level revealed a 100% categorisation of market-ready and young wines in terms of cultivar and 77.85% categorisation of a combination of market-ready and young wines in terms of grape cultivar. This illustrates the validity of polyphenols for studies pertaining to grape cultivar discrimination.

As part of a broader study that investigated techniques for the rapid induction of the needed ageing character in brandy products, the effect of oak wood toasting on quality and chemical composition of oak wood extracts and matured and unmatured pot-still brandy, is reported on. Extracts, prepared from oak chips supplied by a South African cooper, and from commercially obtained oak, and representing different oak types and levels of toasting (i.e. untoasted, light, medium and heavy), were added to 70% (v/v) unmatured pot-still brandy and stored for eight months in glass containers (Schott bottles) at room temperature, or in the case of controls, below 0°C. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived congeners by means of HPLC and GC. Toasted, as opposed to untoasted oak, gave acceptable extracts, the best overall quality pot-still brandies and generally higher concentrations of volatile (GC-determined) and less volatile (HPLC-determined) wood-derived congeners. Toasting provoked an important separation as indicated by discriminant analysis.

The purpose of this study was to investigate the use of different wood types and treatments, and extraction media to induce rapid ageing of brandy. Extracts were prepared from American and French oak, specially prepared and supplied by a cooper, and from commercially obtained oak; both representative of different toasting levels, including untoasted, light, medium and heavy toasted. To extract the wood components, wood chips in either 55% (v/v) neutral wine spirits or water media were boiled under reflux. Distillation was followed by either open (higher boiling temperature) or closed (vacuum or reduced pressure – lower boiling temperature) concentration of the decanted solvent by 45, 65 and 85% (v/v). The concentrated extracts were fortified. Screened extracts were added to unmatured pot-still brandy and aged for eight months at room temperature in glass containers. Controls were stored below 0°C. Matured and unmatured (control) pot-still brandy samples were analyzed for wood-derived congeners by means of HPLC and GC. This article focuses on the effects of the extraction media, and on level and method of concentration (open and reduced pressure) on sensory quality and chemical composition. The treatments that gave acceptable extracts, and the best overall quality pot-still brandy were those that entailed (1) using ethanol instead of water as extraction medium, and (2) levels of concentration above 45% (v/v). Open and reduced-pressure concentrations showed little difference in the quality of the products yielded. Treatments yielding the most acceptable extracts and best overall quality pot-still brandy generally also contained higher concentrations of volatile and less volatile wood-derived congeners. Multivariate data analysis was conducted on the pot-still brandy samples representing the different treatments. Discriminate analysis provided better separation of samples than principal component analysis.

Pinotage and Cabernet franc grape must were inoculated with Saccharomyces cerevisiae and Torulaspora delbrueckii yeasts. Differences in colour were observed between Pinotage (S. cerevisiae) and Pinotage (T. delbrueckii) wines, whereas differences in berry and herbaceous character were observed between Cabernet franc (S. cerevisiae) and Cabernet franc (T. delbrueckii) wines. Mouthfeel properties between treatments for both wines were not significantly different. Overall quality was slightly higher in wines inoculated with T. delbrueckii compared to wines inoculated with S. cerevisiae. Anthocyanins and flavanols measured in Pinotage wines made with T. delbrueckii were higher compared to Pinotage must inoculated with S. cerevisiae. Cabernet franc wines made with S. cerevisiae were higher in anthocyanin glycoside and flavanol concentrations compared to Cabernet franc wines made with T. delbrueckii. Insignificant differences in acetylated and coumarylated anthocyanins were evident between Cabernet franc (S. cerevisiae) and Cabernet franc (T. delbrueckii) wines. Principal component analysis showed that epigallocatechin gallate, epicatechin gallate, procyanidin B2, peonidin 3-O-glucoside, delphinidin 3-(6-acetyl) glucoside, petunidin 3-(6-acetyl) glucoside, malvidin 3-(6-acetyl) glucoside and malvidin 3-O-glucoside concentrations were highest in Pinotage wines inoculated with T. delbrueckii. Cabernet franc wines inoculated with S. cerevisiae yeasts were highest in malvidin 3-(6-p-coumaroyl) glucoside, petunidin 3-(6-p-coumaroyl) glucoside, petunidin 3-O-glucoside, epicatechin gallate and epigallocatechin gallate concentrations. Total anthocyanins were highest in Pinotage (S. cerevisiae) wines and Cabernet franc (T. delbrueckii) wines. Flavanols were highest in Pinotage (T. delbrueckii) and Cabernet franc (S. cerevisiae) wines. It is evident from the results that yeast species has an impact on the flavonoid concentrations within a grape variety.