SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Chardonnay

32

The study’s aim was to investigate a central tenet of biodynamic philosophy as applied to wine tasting, namely that wines taste different in systematic ways on days determined by the lunar cycle. Nineteen New Zealand wine professionals tasted blind 12 Pinot noir wines at times determined within the biodynamic calendar for wine drinkers as being favourable (Fruit day) and unfavourable (Root day) for wine tasting. Tasters rated each wine four times, twice on a Fruit day and twice on a Root day, using 20 experimenter-provided descriptors. Wine descriptors spanned a range of varietal-relevant aroma, taste, and mouthfeel characteristics, and were selected with the aim of elucidating both qualitative and quantitative aspects of each wine’s perceived aromatic, taste, and structural aspects including overall wine quality and liking. A post-experimental questionnaire was completed by each participant to determine their degree of knowledge about the purpose of the study, and their awareness of the existence of the biodynamic wine drinkers' calendar. Basic wine physico-chemical parameters were determined for the wines tasted on each of a Fruit day and a Root day. Results demonstrated that the wines were judged differentially on all attributes measured although type of day as determined by the biodynamic calendar for wine drinkers did not influence systematically any of the wine characteristics evaluated. The findings highlight the importance of testing experimentally practices that are based on anecdotal evidence but that lend themselves to empirical investigation.

Concepts: Qualitative research, Taste, Wine, Chardonnay, Wine tasting descriptors, Wine tasting, Pinot noir, New Zealand wine

28

Sauvignon blanc wines are produced under a wide variety of winemaking conditions, some of which include different fruit-ripening levels, cold soaks and the use of fining agents and inert gases. Anecdotal evidence suggests that sensory variations among these wines may have to do with their phenolic composition and concentration. Therefore the aim of this work was to study the effects of different winemaking conditions typically used in Chile on the phenolic composition and concentration of Sauvignon blanc wines.

Concepts: Oenology, Fermentation, Noble gas, Gases, Cabernet Sauvignon, Sauvignon blanc, Chardonnay, Chilean wine

28

The evolution of the varietal thiol 3-mercaptohexanol acetate (3MHA) and other key aroma compounds has been monitored in New Zealand Sauvignon blanc wines stored for 1 year at three different temperatures (5, 10 and 18 °C). The main processes that occurred in the Sauvignon blanc wines during bottle ageing were hydrolysis of 3MHA and other acetate esters, hydrolysis of ethyl esters of fatty acids, and the formation of ethyl esters of branched acids. The kinetic parameters of ester hydrolysis, including reaction rate constants and activation energies, were determined, which allow prediction of future wine composition based upon storage temperature and time. It was found that 3MHA had the highest reaction rate constant, meaning that this compound is the most unstable, particularly at higher storage temperatures, and that it disappeared very fast during wine storage.

Concepts: Fatty acid, Ester, Reaction rate constant, Wine, Fermentation, Cabernet Sauvignon, Sauvignon blanc, Chardonnay

27

Wine aging is an important process to produce high-quality wines. Traditionally, wines are aged in oak barrel aging systems. However, due to the disadvantages of the traditional aging technology, such as lengthy time needed, high cost, etc., innovative aging technologies have been developed. These technologies involve aging wines using wood fragments, application of micro-oxygenation, aging on lees, or application of some physical methods. Moreover, wine bottling can be regarded as the second phase of wine aging and is essential for most wines. Each technology can benefit the aging process from different aspects. Traditional oak barrel aging technology is the oldest and widely accepted technology. The application of wood fragments and physical methods are promising in accelerating aging process artificially, while application of micro-oxygenation and lees is reliable to improve wine quality. This paper reviews recent developments of the wine aging technologies. The impacts of operational parameters of each technology on wine quality during aging are analyzed, and comparisons among these aging technologies are made. In addition, several strategies to produce high-quality wines in a short aging period are also proposed.

Concepts: Wine, Oenology, Fermentation, Cabernet Sauvignon, Oak, Chardonnay, Sangiovese, Chilean wine

27

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.

Concepts: Multivariate statistics, Principal component analysis, Wine, Cabernet Sauvignon, Grape varieties, Chardonnay, Chilean wine, International variety

27

The authenticity, the grape variety, the geographical origin and the year of vintage of wines produced in Germany were investigated by 1H-NMR spectroscopy in combination with several steps of multivariate data analysis including Principal Component Analysis (PCA), Linear Discrimination Analysis (LDA) and Multivariate Analysis of Variance (MANOVA) together with Cross-Validation (CV) embedded in a Monte-Carlo resampling approach (MC) and others. A total of about 600 wines were selected and carefully collected from five wine-growing areas in the southern and south-western part of Germany. Microvinified wines according to protocol of EU regulation 2729/2000 for EU Wine Database as well as wines from cooperative wine-growers associations, wine manufacturers and estates were analyzed. Simultaneous saturation of the resonances of water and ethanol by application of a low power eight-frequency bandirradiation using shaped pulses allowed for high receiver gain settings and hence optimized signal-to-noise ratios. Correct prediction of classification of the grape varieties of Pinot noir, Lemberger, Pinot blanc/Pinot gris, Müller-Thurgau, Riesling and Gewürztraminer of 95 % in the winepanel was achieved. Not only pure grape wines could be separated but also mixtures of wines from different grape varieties up to 15 % were differentiated. The classification of the vintage of all analyzed wines from different grape varieties, different enological technologies and different wine growing regions by means of chemometrics resulted in a correct prediction of 97% resp. 96 % of vintage 2008 (n=318) and 2009 (n=265). The geographic origin of all wines from the largest German wine producing regions Rheinpfalz, Rheinhessen, Mosel, Baden and Württemberg could be predicted 89% correctly on average by means of chemometrics. The information on latent parameters like grape variety, origin, vintage, technology etc. is coded in multivariate patterns of multiple parameters in the NMR spectra rather than coded in single spectral markers. The complete NMR spectra involves more information than all individual compounds together (synergetic effect). Each NMR spectrum could be regarded as the individual “fingerprint” of a wine sample which includes information about variety, origin, vintage, physiological state, technological treatment and others.

Concepts: Nuclear magnetic resonance, Multivariate statistics, Vitis vinifera, Wine, Grape, Cabernet Sauvignon, Chardonnay, German wine

27

BACKGROUND: The aim of this work was to study for the first time the volatile compounds and olfactory profile of La Rioja red wines made with the local varieties Vitis vinifera cv. Monastel and Maturana Tinta de Navarrete, using Tempranillo as a reference variety. The impact of vintage on these compounds was also evaluated, and chemometric techniques were applied to achieve a possible differentiation of the wines. RESULTS: A clear classification of wines according to grape variety and vintage was obtained. Volatile compounds that differentiated wines by grape variety were varietal aromas whereas vintage was mainly differentiated by compounds formed during the alcoholic fermentation and extracted from wood during the elaboration process in wood barrels. Sensory analysis also allowed differentiation of wines by grape variety. Tempranillo wines were characterized by liquorice notes, whereas Maturana Tinta de Navarrete wines were the least fruity and showed herbaceous and pepper notes. The sensory profile of Monastel varied between vintages. CONCLUSION: These minor grape varieties could provide a good alternative to the most widespread variety in La Rioja, Tempranillo. The use of these varieties produced wines with their own personality and different aromatic profile from other wines in the market.

Concepts: Vitis vinifera, Wine, Fermentation, Grape, Cabernet Sauvignon, Grape varieties, Tempranillo, Chardonnay

24

New Zealand Sauvignon blanc (SB) wines are characterised by a distinctive combination of tropical-fruity and green-herbaceous aromatic compounds. The influence of sunlight exposure of grape clusters on juice and wine composition was investigated, with the aim of manipulating aromatic compounds in SB wine. In the absence of basal leaf removal SB clusters naturally exposed to sunlight were riper than shaded clusters, evidenced by higher total soluble solids (TSS) and proline, and lower malic acid, 3-isobutyl-2-methoxypyrazine (IBMP) and arginine. Volatile thiols in wines did not differ between shaded and exposed clusters. At equivalent TSS, cluster exposure had little or no effect on malic acid concentration. Conversely, wine from shaded clusters had almost double the IBMP concentration of wine from exposed clusters at equivalent TSS. The effects on SB juice and wine composition of natural variations in cluster microclimate are not comparable with the effects of cluster exposure created through leaf removal.

Concepts: Vitis vinifera, Wine, Fermentation, Cabernet Sauvignon, Sauvignon blanc, Chardonnay, Bordeaux, Chilean wine

24

The current paper analyses the evaluation of the costs and benefits of French wineries (N=69) participating in the sustainability program Terra Vitis, a widespread environmental certification scheme within the French wine industry.

Concepts: French language, France, Cabernet Sauvignon, Chardonnay, Italian wine, Table wine, Terroir, French wine

24

This study investigated the potential to improve wine aroma by applying two inactive dry yeast products (IDYs) at the onset of ripening on Sauvignon Blanc grapes. Both products led to increased reduced glutathione concentrations in the grape juice and corresponding wines, as well as differences in individual higher alcohol acetates (HAAs) and ethyl esters of straight chain fatty acids (EEFAs) at the end of fermentation. After two months of storage, a significantly slower decrease of EEFAs and to a lesser extent of HAAs was found for wines made from grapes with IDY applications. These wines also resulted in significantly slower synthesis of ethyl esters of branched acids, whereas varietal thiols were altered in a product-specific manner. The modifications in the wine chemical composition were also sensorially corroborated. This study showed that vineyard additions of IDY products directly on the grapes at the onset of ripening have a subsequent benefit to the production and preservation of aroma in wines.

Concepts: Alcohol, Ethanol, Yeast, Wine, Fermentation, Cabernet Sauvignon, Sauvignon blanc, Chardonnay