Aging In Oak Barrels Research Articles

Impact of Different Wood Types on the Chemical Composition and Sensory Profile of Aged Tsipouro: A Comparative Study

The production of high-quality aged marc spirits includes a minimum period of six months of ageing in oak barrels. Lastly, producers are interested in alternative botanical origin wood. The present study is aimed at investigating the influence of Greek oak (Quercus trojana) and Greek chestnut (Castanea sativa) compared with French (Quercus petraia) and American oak (Quercus alba) on the chemical composition and sensorial characteristics of aged tsipouro, produced from marc from the Black Muscat variety. Gas chromatography–olfactometry–mass spectrometry (GC–O–MS) was used to identify volatile compounds of the aged tsipouro. Also, colour and polyphenol measurements were made, and an organoleptic evaluation was performed by 16 trained tasters. The findings revealed rather similar results between the tsipouro made from different wood species, especially between Greek and French oaks, and relative differentiation for that of chestnut. All the aged distillates exhibited a pleasant and rich aromatic potential, dominated by floral and fruity terpene varietal aromas as well as wood-related volatiles. Chestnut, with a high phenolic potential, gives pleasant organoleptic effects over time and can be an alternative wood for ageing spirits. This research highlights the importance of wood selection in the tsipouro ageing process and enables the use of Greek wood species in the ageing of spirits.

Modifications in aroma characteristics of ‘Merlot’ dry red wines aged in American, French and Slovakian oak barrels with different toasting degrees

Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines. In the present study, the aroma compounds were analyzed from the ‘Merlot’ dry red wines, which were fermented in two types of fermenters (stainless steel tank and rotated oak barrel) and aged in six types of oak barrels (three geographic origins × two toasting degrees) for different time (0, 3, 6 and 9 months, respectively). Results showed that 30 volatiles were associated with barrels and increased during oak aging. The fermenters could influence the intensities of the toast, leathery, smoky, fruity, floral and caramel aromas. The concentration of whisky lactone, eugenol, cis-isoeugenol, and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels. The concentrations of guaiacol, syringol, trans-isoeugenol, furfural alcohol, vanilla, cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones. The compounds originating from the barrels could be used to distinguish the types of different barrels, but the other general grape-derived and fermentation-derived volatiles could not. The fermenters, oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged ‘Merlot’ dry red wines, but the influence of the geographic origin was not obvious.

Characterization of the Oxygen Transmission Rate of New-Ancient Natural Materials for Wine Maturation Containers.

Today, there is a trend in enology promoting a return to the use of old natural materials for the manufacture of storage and maturation wine tanks. One of the most sought-after characteristics of these materials is their permeability to oxygen from the atmosphere to improve wines without this being a harmful process. The reference performance in wine aging is, without doubt, the oak barrel for its ability to oxidize wines in a controlled way, thus improving them. It would be possible to mature wines in containers in which the use of wood is not obligatory, as opposed to aging in oak barrels or foudres. This work presents the results of oxygen permeation analysis under test conditions typical of a tank containing wine, using materials, such as concrete and granite. The oxygen permeability of the materials tested was very diverse, typical of natural materials. The results showed that earthenware presents an excessive permeability, not only to atmospheric oxygen, but also to liquids and needs treatment before being used in liquid containers. Claystone and concrete can be impermeable to liquids, but maintain permeability to atmospheric oxygen—making them candidates for use in permeable tanks for wine maturation. Finally, granite has some very interesting characteristics, though thickness control is required when calculating the desired oxygen transmission rate.

New System to Increase the Useful Life of Exhausted Barrels in Red Wine Aging

In recent years, consumers of red wines have demanded aged wines with intense color and a well-integrated fine wood bouquet. Traditionally, wines with these characteristics have been obtained from aging in oak barrels. This type of vinification incurs high costs, including costs associated with the acquisition and use of oak barrels. After five or six vinifications, these barrels are no longer capable of providing an adequate contribution of wood compounds to the wine, because of the exhaustion of their transfer capacity. An alternative to extend the life of these barrels is the introduction of toasted oak staves inside the barrel. In this study, a comparative analysis of the aging of a red wine in new and renewed barrels was developed by inserting toasted staves and analyzing the wine in its different stages, as well as its physical, chemical, and colorimetric characteristics. This study confirms that the use of insert staves anchored in exhausted barrels helps to prolong the useful life of barrels, while maintaining quality assurance.

Validation of a mass spectrometry method to identify and quantify ellagitannins in oak wood and cognac during aging in oak barrels

Ellagitannins are the main extractible phenolic compounds in oak wood; the monomers vescalagin and castalagin, lyxose/xylose-bearing monomers grandinin and roburin E, dimers roburins A and D and lyxose/xylose-bearing dimers roburins B and C are the principal ones. These compounds are responsible for the high durability of wood and may contribute to the organoleptic quality of wines and spirits (color, astringency, bitterness). Despite their importance, their presence and forms in distilled spirits are not well known. The aim of this work was therefore to develop and validate a method to identify and quantify oak wood ellagitannins in Cognac using high liquid chromatography-triple quadrupole (LC-QQQ) analysis. The method was validated using vescalagin as the standard and by studying sensitivity, linearity in working range, intraday repeatability, and intraday precision in order to quantify individual ellagitannins in this complex matrix.

High-Throughput Sequencing Approach to Analyze the Effect of Aging Time and Barrel Usage on the Microbial Community Composition of Red Wines.

Wine aged in barrels or bottles is susceptible to alteration by microorganisms that affect the final product quality. However, our knowledge of the microbiota during aging and the factors modulating the microbial communities is still quite limited. The present work uses high-throughput sequencing (HTS) techniques to deal with the meta-taxonomic characterization of microbial consortia present in red wines along 12 months aging. The wines obtained from two different grape varieties were aged at two different cellars and compared based on time of wine aging in the barrels, previous usage of the barrels, and differences between wine aging in oak barrels or glass bottles. The aging in barrels did not significantly affect the microbial diversity but changed the structure and composition of fungal and bacterial populations. The main microorganisms driving these changes were the bacterial genera Acetobacter, Oenococcus, Lactobacillus, Gluconobacter, Lactococcus, and Komagataeibacter and the fungal genera Malassezia, Hanseniaspora, and Torulaspora. Our results showed that the oak barrels increased effect on the microbial diversity in comparison with the glass bottles, in which the microbial community was very similar to that of the wine introduced in the barrels at the beginning of the aging. Furthermore, wine in the bottles harbored higher proportion of Lactobacillus but lower proportion of Acetobacter. Finally, it seems that 1 year of previous usage of the barrels was not enough to induce significant changes in the diversity or composition of microbiota through aging compared with new barrels. This is the first meta-taxonomic study on microbial communities during wine aging and shows that the microorganism composition of barrel-aged wines was similar at both cellars. These results hint at the possibility of a common and stable microbiota after aging in the absence of exogenous alterations. Further corroborations on the current outcome would be valuable for the comparison and detection of microbial alterations during aging that could potentially prevent economic losses in the wine industry.

Evolution of the Phenolic Fraction and Aromatic Profile of Red Wines Aged in Oak Barrels.

Various changes occur in red wine during aging in oak barrels. Among these, the variation of the polyphenolic fraction and the transfer of aromatic compounds to the wine from oak wood are of great importance. The aim of the present work is to compare the chemical composition of wines aged in different new oak barrels with similar commercial denominations. During 8 months, the total polyphenol index (TPI), color parameters, anthocyanins and pyranoanthocyanins, and wood aromatic compounds were periodically evaluated. The measurement of the TPI and color parameters was similar in all wines, but significant differences were found in total anthocyanin and vitisin content and in certain aromatic compounds belonging to volatile phenols, furanic compounds, and phenolic aldehydes. The results obtained indicate the need for the winemaker to carry out preliminary tests in order to be able to choose the wood that best suits the sensorial profile of the wine.

Formation and evolution profiles of anthocyanin derivatives and tannins during fermentations and aging of red wines

The target of this paper is the study of anthocyanin and tannin extraction from red grape during maceration, the formation of new pigments, and the evolution profiles of anthocyanin derivatives and tannins during the alcoholic and malolactic fermentations and aging in oak barrels and steel vats. 2 anthocyanins, 38 anthocyanin derivatives and 37 tannins were monitored. Formation of all classes of anthocyanin derivatives starts quickly after anthocyanin extraction from grape. Their maximum levels are reached a few days after apex of anthocyanins during maceration/alcoholic fermentation. Indirect condensation derivatives showed less stable behavior than that of the direct flavanol–anthocyanin products during fermentations and aging. Within pyranoanthocyanins, vitisin B had more instability than vitisin A. Extraction of tannins from grape occurs slower than that of anthocyanins. Major tannins are procyanidin homodimers with B bond (45% of total tannins after fermentations), followed by monomers (around 25%) and mixed B dimers (more than 10%). Tannins suffer a general continuous decrease during aging, with increasing relevance of more oxygenated tannins as aging advances. Fermentations are crucial stages in the formation of anthocyanin derivatives. In contrast, aging causes a continuous degradation for nearly all classes of anthocyanin derivatives and tannins, with a more stable behavior for some of them. Thus, establishing with confidence which enological conditions favor each type of derivative during fermentation is an important goal for future research. This work studies many individual compounds, involves exhaustive sampling and covers the different winemaking stages at an industrial winemaking scale, contributing to a more complete vision.

Effects of aging in oak barrels on the trans-resveratrol and anthocyanin concentration of red wines from Hungary

Polyphenol compounds in grapes and wines are of paramount importance: they have a key role in determining wine quality, and also the beneficial health effects of moderate red wine consumption are well-known. The polyphenol concentration of wines is determined mostly by: a) their concentration in the grapes and b) the production technology, particularly the time and type of aging. Our goal was to determine the trans-resveratrol and anthocyanin contents of Hungarian red wines under different manufacturing conditions, by monitoring the 24-month aging process – using barrique and oak barrels – with semi-annual sampling, without considering vintage. We have chosen to determine polyphenol components that could originate from either the grapes, or be produced during the wooden barrel aging. Both the aging time and the wine variety had non-negligible effects on the changes in the concentrations of the studied components, whereas the wooden barrel type had not.

Use of Oak Fragments during the Aging of Red Wines. Effect on the Phenolic, Aromatic, and Sensory Composition of Wines as a Function of the Contact Time with the Wood

The use of oak fragments allows wine cellars to reduce costs and the length of wine aging compared to traditional aging in oak barrels in the winery. The main objective of this work was to study the effect of the use of oak fragments on the volatile, phenolic, and organoleptic characteristics of Tempranillo red wines, as a function of the contact time between the wood and the wine. The results showed important changes in the wines’ colorimetric parameters after two months of contact time. Extraction kinetics of volatile compounds from the wood was highest during the first month of contact for chips, variable for staves, and slower and continuous over time for barrels. Wines macerated with fragments showed the best quality in short periods of aging, while barrel-aged wines improved over the time they spent in the barrel. In addition, the results allowed an analytical discrimination between the wines aged with oak fragments and those aged in oak barrels, and between chips and staves, just as at the sensory level with triangular tasting tests. In conclusion, the use of oak fragments is a suitable practice for the production of red wines, which may be an appropriate option for wines destined to be aged for short periods.

Study of the Interaction of Anthocyanins with Phenolic Aldehydes in a Model Wine Solution.

Aldehydes may be present in wines as a result of metabolic processes during wine fermentation or through oxidation and extraction from wood during wine aging in oak barrels. Apart from acetaldehyde, the most abundant aldehyde in wine, other aldehydes such as furfural and more recently vanillin have shown to contribute to the formation of more stable pigments. The copigmentation effect of phenolic molecules, including flavanols and anthocyanins themselves, has been previously evaluated in wine and model solutions, and even the effect of aldehydes related to wine aging has been documented at different pHs and molar ratios. The copigmentation phenomenon is observed by hyperchromic effects and bathochromic shifts of λmax, and, in the same time, the presence of larger molecular weight pigments, potentially less susceptible to degradation, was followed up. This experimental work intended to evaluate the potential of five different aldehydes, all of which are safe for human consumption and are used in the food industry, to the formation of pyranoanthocyanin-like and polymeric pigments in the model solution.

Sensory characterization of the astringency of commercial Uruguayan Tannat wines

Astringency is one of the most important characteristics that define the quality of red wine, and is of particular relevance for Tannat, Uruguayan emblematic red wine variety. Astringency is a time-dependant and complex sensory characteristic, related to several sensations, or sub-qualities, that can be simultaneously perceived. The aim of the present study was to obtain a sensory characterization of the astringency of commercial Uruguayan Tannat wines. Forty samples with different characteristics in terms of vintage, price segment and aging in oak barrels were assessed by a panel of 9 trained assessors. Total astringency intensity was evaluated using time-intensity (TI), while astringency sub-qualities were described using a check-all-that-apply (CATA) question composed of sixteen terms. TI and the CATA question provided different information on the astringency of Tannat wines. Regarding global astringency, samples mainly differed in intensity-related parameters rather than in the development of astringency over time, although the variability was moderate. A wide range of sub-qualities, from silky and velvety to harsh and aggressive were used to describe the astringency of the evaluated wines. Four groups of samples with different astringency characteristics were identified, but this sorting was not related to vintage, price segment or aging in oak barrels. Further research is necessary to better understand how astringency characteristics are influenced by production variables, and to understand their relationship to consumers' and experts' perceived quality of Tannat wines.

Evolutions of volatile sulfur compounds of Cabernet Sauvignon wines during aging in different oak barrels

The evolution of volatile sulfur compounds (VSCs) in Cabernet Sauvignon wines from seven regions of China during maturation in oak barrels was investigated. The barrels were made of different wood grains (fine and medium) and toasting levels (light and medium). Twelve VSCs were quantified by GC/FPD, with dimethyl sulfide (DMS) and methionol exceeding their sensory thresholds. Most VSCs tended to decline during the aging, while DMS was found to increase. After one year aging, the levels of DMS, 2-methyltetrahy-drothiophen-3-one and sulfur-containing esters were lower in the wines aged in oak barrels than in stainless steel tanks. The wood grain and toasting level of oak barrels significantly influenced the concentration of S-methyl thioacetate and 2-methyltetrahy-drothiophen-3-one. This study reported the evolution of VSCs in wines during oak barrel aging for the first time and evaluated the influence of barrel types, which would provide wine-makers with references in making proposals about wine aging.

C-glucosidic ellagitannin concentrations variability during the years in Syrah wines from Languedoc vineyard

C -Glucosidic ellagitannins, which are the main polyphenolic compounds in oak heartwood, are extracted by wine during aging in oak barrels. The C -glucosidic ellagitannins were extracted and purified (> 95% pure) from Quercus robur heartwood and the hemisynthesis of acutissimins A and B, as well as that of epiacutissimins A and B were performed in an acidic organic solution to identified and quantified their concentration ranges by HPLC-UV-MS in 17 Syrah wine samples from the same cultivar area, Languedoc, same quality wood of French oak barrel, same time of oak barrel ageing (12 months) and different ageing period (years from 1999 to 2011). Unlike our first hypothesis, the linear relationship of a reduction in the total content of ellagitannins with the time spent in bottles is not visible.

Malolactic fermentation before or during wine aging in barrels

Malolactic fermentation (MLF) and aging in oak barrels are two oenological processes which modify the composition and sensory characteristics of the wines. However, there are few studies on the MLF in barrels.This work compares wines in which MLF is carried out in steel tanks and then aged in oak barrels, with wines in which MLF has been carried out in barrels.MLF occurs faster in barrels and while the fundamental structure of the wine is virtually identical, there is less color loss.Some groups of volatile compounds vary significantly depending on whether MLF takes place in tanks prior to aging or in the oak barrels themselves. It was shown that in this latter case, wines were obtained with slightly higher concentrations of methoxy-phenols and approximately double amount of whisky-lactones and furanic compounds.

Imaging of oxygen transmission in the oak wood of wine barrels using optical sensors and a colour camera

Background and Aims Wine ageing in oak barrels is characterised by a series of physical and chemical processes, in many of which oxygen plays an important role. Therefore, to control better this phase of winemaking, it is not enough to know that oxygen penetrates into the barrel through the oak wood; it is also important to know how oxygen moves through the wood into the barrel, in what quantity and which factors are involved. Methods and Results We attempted to answer these questions with a high-resolution colour camera, ratiometric calibration and a planar optode with which the two-dimensional distribution and dynamics of oxygen within an oak barrel stave were studied. It was possible to make two-dimensional measurements when combined with microscopic optics and an appropriate camera, which permitted the measure of the transmission of oxygen into the barrel through the oak stave and the study of the mechanism of transmission. The trial was applied to both dry and wet oak wood, which revealed how the moisture content of the wood influenced oxygen transmission. The measurements were made in an airtight chamber under controlled temperature and pressure, which accurately reproduced the conditions of a stave in an oak wood barrel filled with liquid. Conclusion We were able to visualise the diffusion of oxygen in both dry and in wet French oak wood under conditions similar to those operating in a barrel. The moisture content of the wood influenced the oxygen transmission rate (OTR) through the wood. Significance of the Study For the first time, the dissolved oxygen dynamics and two-dimensional distribution of oxygen within the thickness of a barrel stave have been demonstrated. Wood water saturation is a key factor in the diffusion of oxygen through wood with barrel OTR decreasing during the ageing period.

Influence of Wood Barrels Classified by NIRS on the Ellagitannin Content/Composition and on the Organoleptic Properties of Wine

Ellagitannins are extracted from oak wood during wine aging in oak barrels. This research is based on the NIRS (Oakscan) oak wood classification according to their index polyphenolic (IP) (between 21.07 and 70.15). Their level in wood is very variable (between 5.95 and 32.91 mg/g dry wood) and influenced their concentration in red wine (between 2.30 and 32.56 mg/L after 24 months of aging) and thus their impact on wine organoleptic properties. The results show a good correlation between the NIRS classification and the chemical analysis (HPLC-UV-MS and acidic hydrolysis procedure) and with the wood ellagitannin level, the ellagitannin extraction kinetic, and the ellagitannins evolution in red wine (Cabernet Sauvignon). Moreover, a correlation between the NIRS classification and the increasing intensity of some wood aromas (woody, spicy, vanilla, and smoked/toasted), flavors (bitterness and astringency), and a decreasing intensity of fruitiness was also observed.

Effects of electric field treatments on phenol compounds of brandy aging in oak barrels

Abstract The effects of applying an electric field (EF) treatment with 1 kV/cm (50 Hz) on brandy stored in 5-L and 2-L oak barrels, respectively, for over 14 months to simulate the natural aging process were investigated in this paper, as compared with brandy sample naturally aged in 225-L oak barrels. Results demonstrated that the content of phenol compounds in brandy such as tannins, total phenols as well as volatile phenols were significantly increased after treatment by EF, with tannin concentration of the brandy treated by EF being 54.4% and 43.9% higher than those of the control brandy after 14 months of maturation in 5-Land 2-L barrels, respectively. On the other hand, the chromatic aberration of the brandy treated by EF for 14 months was 19.2% and 24.9% higher than the control in 5-L and 2-L barrels, respectively. It was also demonstrated that the EF treated samples in 5-L barrels for 7 months and in 2-L barrels for 5 months exceeded the content of tannins of those naturally aged for 12 months in 225-L oak barrels used in the brandy industry. Ten kinds of phenol compounds were identified, which could be divided into three categories based on clustering analysis, and the kinetic model of oak phenol compounds extracted by brandy demonstrated that EF treatment played a positive role in accelerating the extraction of phenol compounds and its effect was more significant than the size of barrel. The current study demonstrated that application of EF treatment directly on oak barrel is a promising and feasible technology to speed up brandy maturation. Industrial relevance The current study demonstrated that application of electric field treatment directly on oak barrels is a promising and feasible technology to speed up brandy maturation for the industry.

Antimicrobial activity of ozone. Effectiveness against the main wine spoilage microorganisms and evaluation of impact on simple phenols in wine

Background and Aims: Microbial contamination affects winemaking, especially after fermentation, e.g. wine ageing in barrels or in contact with oak pieces, when spoilage microbes find an environment favourable for their development. Ozone was evaluated as a sanitising agent in order to assess its potential to prevent microbial spoilage occurring during ageing of wine in barrels using a model system based on barrel wood. Methods and Results: Fifty microorganisms of oenological significance were evaluated for their spoilage potential in the barrel. Ethanol resistance, biofilm formation and production of volatile phenols were studied using physiological tests. The effectiveness of ozone in eliminating microorganisms was evaluated in aqueous solution at several cell and ozone concentrations. At a high cell concentration, the presence of organic matter reduced the effectiveness of ozone. At a cell concentration of under 103 CFU/mL, typical of wine cellars, ozone was able to eliminate microorganisms. Resistance to ozone was observed in diverse microorganisms, and this feature is linked to their ability to produce a biofilm. The reduction in simple phenols obtained from oak wood was tested by treating oak chips, routinely used in the wine industry, with an increasing dose of ozone. There was no statistical difference in the phenolic composition of wine treated with six commercial chips. Only a significant exposure of the chips to ozone caused a 33%reduction in the initial content of gentisic acid. Conclusions: Ozone was shown to be a highly effective sanitising agent without interfering with the profile of the phenolic substances extracted from oak. The application of ozone for barrel sanitising may be a feasible solution for the prevention of wine spoilage during ageing in oak barrels. Significance of the Study: A survey of the effect of ozone on a large number of microorganisms and phenolic compounds of oenological significance, considering some technological variables, is reported.

Polyphenolic ellagitannins and gallotannins: Structures, synthesis and biological activity - from folk medicine to chemical biology via wine sciences

Hydrolyzable tannins constitute a class of plant bioactive polyphenols primarily composed of ellagitannins and gallotannins derived from the metabolism of gallic acid. Ellagitannins feature galloyl units esterified to a sugar core, usually glucose, and characterized by the presence of biaryl and diaryl ether bonds between some or all of their galloyl units.[1] Among ellagitannins, there exists a subclass of structurally unique nonahydroxyterphenoyl (NHTP)-bearing C-glucosidic molecules featuring an open-chain glucose core and exemplified by vescalagin. The fact that some of these C-glucosidic ellagitannins are found in wine as a result of aging of this beverage in oak-made barrels provided us with the impetus to examine their chemical reactivity and biological activity. Indeed, during aging in oak barrels, the hydroalcoholic and slightly acidic (i.e., pH 3–4) wine solution enables the solid-liquid extraction of these ellagitannins. Once in the wine solution, some of these natural products such as vescalagin can capture grape-derived nucleophilic entities such as the flavanols catechin and epicatechin and the anthocyanin oenin to furnish condensation products, some of them having been postulated as active principles in Asian herbal medicines.[2] Of pharmacological importance is the fact that several of these found-in-wine ellagitannin hybrids are much more potent than etoposide (VP-16) at inhibiting in vitro the anti-cancer target DNA topoisomerase IIa.[2a,b] Furthermore, we recently discovered that vescalagin is capable of drastically perturbing the actin cytoskeleton by interacting selectively with the actin filaments, both in vitro and in cellulo.[3] Moreover, gallotannins, in which galloyl units and/or depsidically-linked chains of galloyl units are usually esterified to a glucopyranose core, and some of their simpler precursors exhibit some interesting properties with possible applications as antifibrillogenic agents. Thus, the various biophysico-chemical properties we unveiled for these hydrolysable tannins will be presented and their exploitation in the development of therapeutic agents discussed during this lecture.