Differences in the phenolic composition and sensory profile between red wines aged in oak barrels and wines aged with oak chips

The aim of this study was to evaluate the similarities or differences in the phenolic composition and the sensory characteristics between wines traditionally aged in new French and American barrels for different periods of time, and wines aged for 30 days with different kinds (different geographical origin al toasting degree) of oak chips. This study was carried out with two grape varieties, Mencía and Tinta del País, and in two consecutive vintages. The results obtained indicated that it was not possible to obtain wines aged with chips with sensory characteristics similar to those aged for a long time in new barrels, independently. However, the results showed that the use of oak chips could be a good alternative for elaborating young wines with slight olfactory and gustative wood notes quite similar to wines aged in new barrels for short periods of time (about three months).     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part II: Merlot wines

The character of Merlot wines after the treatments of micro-oxygenation and subsequent chips addition, as regards the colour-related phenolics, volatile composition and sensory characteristics, was studied. An increase in the degree of polymerisation of red pigments and a decrease in the value of the red component of the colour (a^*) and the degree of co-pigmentation were observed. The concentrations of monomeric anthocyanins and anthocyanin-derived pigments, such as hydroxyphenyl-pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts, significantly decreased. With regard to the wine aroma, the micro-oxygenation produced a decrease of some esters, alcohols and benzenic compounds and increased some terpenes and C₁₃-norisoprenoids. With regard to sensorial analysis, micro-oxygenation treatment resulted in higher scores for the red fruit and spicy attributes and caused the presence of new attributes (nutty and sweet fruit). This technique produces a lower level of the typical oak chip aromas (vanilla and woody) in Merlot wines.     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part I: Petit Verdot wines

In this paper, the effects of micro-oxygenation before malolactic fermentation and oak chip treatments on Petit Verdot red wines have been evaluated. Our attention was focused on the colour characteristics, the phenolic compounds related to the colour of red wine, the volatile compounds, and the sensory characteristics of the wines. The micro-oxygenation treatment promoted the stabilisation of red wine colour by increasing the formation of colour-related phenolic compounds (higher concentrations of pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts). Red wine aroma quality was improved with the addition of oak chips (eugenol and 4-vinyl-guaiacol concentration increased). Micro-oxygenation treatment resulted in higher scores for the plum/currant and spicy attributes, as well as the appearance of tobacco and nutty notes which were absent in the non-treated wines. Nevertheless, the typical oak chip aromas (vanilla and woody) were observed to a lesser extent in wines obtained by micro-oxygenation.     

Volatile composition and sensory characteristics of Chardonnay wines treated with American and Hungarian oak chips

Toasted or non-toasted chips of oak woods of different geographical provenances were macerated in Chardonnay wines (4 g/l) during a period of 25 days. Oak lactones were detected in significant quantities in wines treated with American oak. Only trace amounts of oak lactones were detected in the wines treated with Hungarian oak. Toasting of the oaks increased the quantities of the compounds derived from the thermal degradation of lignin: vanillin, eugenol, guaiacol and its derivatives and the pyrolysis of cellulose and hemicellulose: furfural and 5-methyl furfural, and decreased the concentrations of the two isomers of oak lactones. The concentrations of the majority of the volatile compounds did not present statistically significant differences between 15 and 25 days. However, the wines preferred by the tasters and with maximum intensity of the sensory attributes acquired were those treated with oak chips for 25 days. Chemical and sensorial analyses of wines revealed that the effect of the toasting of oak chips on wine characteristics was greater than the type of oak used. All wines studied were positively evaluated by the panellists.     

Volatile composition of Bobal red wines subjected to alcoholic/malolactic fermentation with oak chips

The effect of wood, in the form of oak chips, on the volatile composition of Bobal red wines caused by adding oak chips at different stages of the fermentation process has been studied. Aroma compounds were isolated by solid phase extraction (SPE) for subsequent analysis by gas chromatography–mass spectrometry (GC/MS). Bobal control wine was produced according to traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose levels (3 and 6 g/L) at different stages of the winemaking process: at one week during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Bobal wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids and ethyl, hexyl and isoamyl acetates than the control wine. A similar, trend was observed for higher alcohols. Higher concentrations of benzene compounds, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF followed by young Bobal oak wines. These results reveal that the point of addition during the winemaking process and the dose level of oak chips used have a significant effect on the volatile composition of Bobal red wines.     

Effect of aging in new oak, one-year-used oak, chestnut barrels and bottle on color, phenolics and gustative profile of three monovarietal red wines

This study provides specific information about the influence of storage in bottle and in 225-L barrels made from oak (new and used for 1 year) and chestnut wood on color indexes, spectrophotometric evaluable polyphenols, anthocyanins, phenolic acids and gustative attributes of three monovarietal red wines (Piedirosso, Cabernet Sauvignon and Merlot). The results of the analysis of variance show that wood type has a significant influence on chromatic characteristics, on vanilline reactive flavans, on low molecular weight phenolics and on astringency of wines. The effect depends on the type of wine. Therefore, both traditional and alternative wood containers could be used as an instrument to regulate the polymerization, oxidation and copigmentation reaction of wine phenolics and the sensory properties of red wine. The maturation in chestnut wood could be an interesting challenge to widen the supply of red wines maturated in wood, but its use needs more care than oak.     

Chemical and sensory changes in white wines fermented in the presence of oak chips

Summary Three samples of French oak and one sample of American oak were analyzed by different gas chromatographic-mass spectrometric (GC/MS) methods. Two methods of quantifying the main volatile compounds in oak wood were compared, namely, Direct Thermal Desorption coupled with GC/MS and analysis of mixtures of water-ethanol and wines that had been in contact with oak chips by extraction using an organic solvent followed by GC/MS analysis of the extract. The ratio of the two oak lactones released into the wine by the oak chips was the same as the ratio observed in original, untreated wood. These substances are of particular sensory importance in wines aged in oak wood barrels. Thus, the use of oak chips in white wines may be advantageous. The wines steeped with the oak chips improved their acceptability rating 2 points on a scale of 9.     

Effects of composition,storage time,geographic origin and oak type on the accumulation of some volatile oak compounds and ethylphenols in wines

The aim of this work was to study the effect of different parameters on the accumulation of volatile oak compounds and ethylphenols in red barrel-aged wines. For this, 510 wines, from four different geographic zones and aged for various times in different oak barrel types were analysed. The results of the statistical analysis showed that the compounds were in four groups, accounting for 82.99% of the variance. The enological parameters did not present correlation with any of these four groups. The wines that remained longer in oak barrels presented, in general, higher concentrations of the studied compounds. Three of the four geographic zones were similar to each other. The oak barrel type affected the value of the ratio cis/trans, but it did not affect the accumulation of any of the volatile oak compounds or ethylphenols.     

Changes in the volatile composition of red wines during aging in oak barrels due to microoxygenation treatment applied before malolactic fermentation

Microoxygenation is a wine-making technique consisting in the addition of small and controlled amounts of oxygen. This study has examined the effect of this technique on the volatile composition of two red single variety wines during two successive vintages. The microoxygenation treatment was applied at the end of alcoholic fermentation and before beginning malolactic fermentation. Once the microoxygenation treatment had finished, wines were aged in new American oak barrels for 12 months. The results obtained showed that the microoxygenation treatment did not cause significant changes in the varietal and fermentation volatile compounds, however microoxygenation slowed down the extraction of some of the volatile compounds extracted from wood. A varietal and vintage effect was also observed for some of the compounds studied.     

Impact of chemical profile on sensory evaluation of tropical red wines

This study evaluated the correlation between the chemical composition of red wines and the sensory perception of the products. The visual, gustatory and flavour attributes of eight samples of tropical red wines were characterised by semi-trained panellists using the check-all-that-apply methodology. Titratable and volatile acidity, pH, contents of ethanol, total polyphenols and anthocyanins, and the chromatic parameters of the red wine samples were determined. The analysis of the correlations between visual attributes and sensory perception indicated that the evaluation of the wine colour attributes can predict other sensory characteristics related to aromas and flavours. This enabled the wine tasters to distinguish subtle variations in the visual attributes of the product. The results of this study indicated that panellists who underwent short-term training can sensorially perceive the influence of physicochemical variables on wine quality. Additionally, the correlation analysis enabled the identification of production adjustments and the understanding of the consumer perception of a complex product.     

Anthocyanin,phenolic composition,colour measurement and sensory analysis of BC commercial red wines

This research established a database of analytical values associated with 173 commercial red wines from 7 vintages (1995–2001), 4 varieties (Pinot noir, Merlot, Cabernet Franc, Cabernet Sauvignon) and 13 vineyard locations within BC. Wines were analyzed for sulfur dioxide, pH, titratable acidity, phenolics, tartaric esters, flavonols, as well as copigmented, monomeric, polymeric, and total anthocyanins. Colour was evaluated using colour density, hue, and L, a¹, b¹ and chroma measurements. The sensory astringent qualities were characterized on a subset of 78 wines, using a panel of 12 judges. The panel evaluated the magnitude of the astringency, astringent aftertaste, oakiness and bitterness, as well as 3 astringent sub-qualities (surface roughness, drying, puckering). Data were analyzed by analysis of variance, principle component analyses, and canonical discriminant analyses to track the influence of variety, vintage and vineyard location. Trends were observable despite large variation in winemaking techniques. Red colour, colour density, copigmented, monomeric, polymeric and total anthocyanins were lowest in Pinot noir and highest in Cabernet Sauvignon wines. Younger wines had higher concentrations of copigmented, monomeric, and total anthocyanins than did older wines. Canonical discriminant analysis of the analytical and sensory determinations were successful in distinguishing the wines according to where the grapes were grown.     

Effect of storage temperature on the chemical composition and sensory profile of Sauvignon Blanc wines

Background and Aims: Most white wines lose fresh and fruity characteristics, associated with volatile esters, during ageing in the bottle. A higher storage temperature accelerates these changes. The aim of this study was to examine the influence of storage temperature on the chemical and sensory properties of Sauvignon Blanc wines. Methods and Results: Three commercially bottled Sauvignon Blanc wines from the 2008 and 2009 vintages were stored at 5, 10, 18°C and at room temperature for 12 months. Wines stored at warmer temperatures (18°C and room temperature) contained lower concentrations of acetate esters, including the prominent varietal thiol 3MHA, and ethyl esters of fatty acids, than the wines stored at cooler temperatures (5 and 10°C). A warmer temperature accelerated the rate of ester hydrolysis. Conversely, the concentrations of ethyl esters of branched acids were higher in wines stored at the warmer temperatures. The sensory profile of the wines was assessed after 12 months for the two 2008 wines and after 8 months for the 2009 wine. The wines stored at cooler temperatures were characterised by higher fruity and fresh vegetal aromas, whereas the wines stored at warmer temperatures exhibited the opposite sensory profile, with dominant woody/smoky/oaky, buttery, flinty and canned asparagus notes. Conclusions: These results indicate that temperature‐dependent hydrolysis processes are critical for Sauvignon Blanc aroma stability during the first year in the bottle. Significance of the Study: Cool storage temperature conditions can significantly increase the shelf‐life of Sauvignon Blanc wines by preserving their fruity and fresh green characters.     

Changes in volatile composition and sensory attributes of wines during alcohol content reduction

A desirable sensory profile is a major consumer driver for wine acceptability and should be considered during the production of reduced‐alcohol wines. Although various viticultural practices and microbiological approaches show promising results, separation technologies such as membrane filtration, in particular reverse osmosis and evaporative perstraction, in addition to vacuum distillation, represent the most common commercial methods used to produce reduced‐alcohol wine. However, ethanol removal from wine can result in a significant loss of volatile compounds such as esters (ethyl octanoate, ethyl acetate, isoamyl acetate) that contribute positively to the overall perceived aroma. These losses can potentially reduce the acceptability of the wine to consumers and decrease their willingness to purchase wines that have had their alcohol level reduced. The change in aroma as a result of the ethanol removal processes is influenced by a number of factors: the type of alcohol reduction process; the chemical‐physical properties (volatility, hydrophobicity, steric hindrance) of the aroma compounds; the retention properties of the wine non‐volatile matrix; and the ethanol level. This review identifies and summarises possible deleterious influences of the dealcoholisation process and describes best practice strategies to maintain the original wine composition. © 2016 Society of Chemical Industry