How to make great wine

Wine... nectar of the gods. We all know it's made from grapes, but what's the #ScienceBehind wine?

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Research Paper

Flavor of cold-hardy grapes: impact of berry maturity and environmental conditions.

Abstract: Since the arrival on the market of high-quality cold-hardy grape varieties, northern winemaking has been developing tremendously in countries traditionally unsuited for grape and wine production. Cold-hardy grapes are mainly interspecific hybrids of Vitis vinifera with Vitis labrusca and Vitis riparia , making their chemical composition distinct from that of V. vinifera varieties traditionally used for winemaking and therefore limiting the use of current knowledge about V. vinifera varieties in the assessment of grape maturity. Consequently, to evaluate the flavor development of cold-hardy grapes in the province of Quebec, Canada, the ripening of Frontenac and Marquette berries in two vineyards located in the southwest (SW) and northeast (NE) areas of the province, starting at the beginning of veraison, was studied. Quality attributes, phenolic compounds, and aroma profiles showed significant changes during maturation. Although full maturity was reached for both Frontenac and Marquette in the SW vineyard (1380 accumulated growing degree days, based on 10 °C), the accumulation of 1035 growing degree days was not sufficient to fully ripen Frontenac and Marquette in the NE vineyard. Principal component analysis showed different ripening patterns for the two studied locations. The longer veraison in the SW vineyard resulted in higher quality attributes and higher flavor development for both Frontenac and Marquette. Under the colder conditions in the NE vineyard, metabolite accumulation was driven primarily by berry growth, and flavor development was limited. Besides growing degree days and technological parameters (total soluble solids, pH, titratable acidity), which provide significant guidelines for maturity assessment in cold climate, phenolic maturity may be followed by the accumulation of hydroxycinnamic esters and flavonoids, although the impact of these compound classes on quality remains to be determined in cold-climate wines. In both Frontenac and Marquette, aromatic maturity was best assessed using the ratio of cis-3-hexenol to trans-2-hexenal, which showed a constant decrease until maturity. Interestingly, a shift in C6 compound profile, illustrated by the progression of the sum of C6 compounds respectively produced from linoleic (C18:2; hexanal and 1-hexanol) and α-linolenic (C18:3; trans-2-hexenol and cis-3-hexenol) acids occurred during ripening, with α-linolenic acid (C18:3) degradation products decreasing in both varieties as maturation approached. At harvest, aroma profiles of both Frontenac and Marquette were dominated by C6 compounds (hexanal, trans-2-hexenal, 1-hexanol, cis-3-hexenol, and hexanoic acid), acetic acid, β-damascenone, and 2-phenylethanol, with Marquette additionally showing significant levels of monoterpenes (linalool, geraniol, and α-citral) and 1-octen-3-ol.

Pub.: 25 Oct '13, Pinned: 08 Nov '16

Research Paper

Influence of closure, phenolic levels and microoxygenation on Cabernet Sauvignon wine composition after 5 years' bottle storage.

Abstract: Wine aging is generally limited by the amount of oxidation, which is dependent on the amount of oxygen entering via the closure. Cabernet Sauvignon wine is well known for its high concentration of tannin, making it an ideal red wine for aging. The impact of closure type after 5 years' bottle aging has been investigated on a 2007 Cabernet Sauvignon red wine, treated with or without polyvinylpolypyrrolidone (PVPP) and micro-oxygenation (Mox). Two oxygen transfer rate (OTR) conditions (16 and 5 µg per day) into 375 mL bottles were obtained by using different synthetic stoppers.Color was evaluated by UV-visible spectrophotometry, carbonyls by 2,4-dinitrophenylhydrazine derivatization, phenolics by high-performance liquid chromatography and sulfur dioxide by the aspiration method. Closure type strongly influenced color parameters involving SO2 bleaching and some phenolics, particularly quercetin, were affected, but there was little effect on carbonyls other than acetaldehyde. PVPP treatment afforded wines with the lowest levels of phenolics and color density, but highest acetaldehyde. Few effects of Mox could be detected.Closure OTR strongly affects sulfur dioxide levels - the primary antioxidant in wine - in aged wine, but phenolic levels substantially alter the secondary reactions of oxidative aging.

Pub.: 17 Apr '14, Pinned: 08 Nov '16

Research Paper

Wine and headache.

Abstract: The notion of migraine attacks triggered by food and beverages has been posited for centuries. Red wine in particular has been acknowledged as a migraine trigger since antiquity when Celsus (25 B.C.-50 A.D.) described head pain after drinking wine. Since then, references to the relationship between alcohol ingestion and headache attacks are numerous. The most common initiator of these attacks among alcoholic beverages is clearly wine. The aim of this review is to present and discuss the available literature on wine and headache.A Medline search with the terms headache, migraine, and wine was performed. Data available on books and written material about wine and medicine as well as abstracts on alcohol, wine, and headache available in the proceedings of major headache meetings in the last 30 years were reviewed. In addition, available technical literature and websites about wine, grapes, and wine making were also evaluated.Full papers specifically on headache and wine are scarce. General literature related to medicine and wine is available, but scientific rigor is typically lacking. The few studies on wine and headache were mostly presented as abstracts despite the common knowledge and patients' complaints about wine ingestion and headache attacks. These studies suggest that red wine, but not white and sparkling wines, do trigger headache and migraine attacks independently of dosage in less than 30% of the subjects.Wine, and specifically red wine, is a migraine trigger. Non-migraineurs may have headache attacks with wine ingestion as well. The reasons for that triggering potential are uncertain, but the presence of phenolic flavonoid radicals and the potential for interfering with the central serotonin metabolism are probably the underlying mechanisms of the relationship between wine and headache. Further controlled studies are necessary to enlighten this traditional belief.

Pub.: 08 May '14, Pinned: 08 Nov '16

Research Paper

New insights into the capacity of commercial wine yeasts to grow on sparkling wine media. Factor screening for improving wine yeast selection.

Abstract: During the production of sparkling wine, wine yeasts are subjected to many stress factors apart from ethanol, which lead to the need to achieve their acclimation in line with various industrial protocols. In the present work, 44 commercial wine Saccharomyces cerevisiae strains and one laboratory strain (BY4742) were firstly subjected to the influence of increasing concentrations of ethanol to cluster the yeasts using discriminant function analysis. Afterwards, non-inhibitory concentration (NIC) and minimum inhibitory concentration (MIC) were estimated, revealing some differences between 24 of these strains. Meanwhile, this study confirms the negative synergistic effect of low pH with ethanol on the maximum specific growth rate (μmax) and lag phase time. Moreover, a negative effect of increasing levels of glycerol in the growth medium was observed. Interestingly enough, an interactive positive effect was found between cysteine and medium-chain fatty acids (MCFA). While cysteine did not have a really significant effect in comparison to the control, it was able to restore the damage caused by MCFA, making the growth rate of cells recover and even reducing the formation of reactive oxygen species. Adequate culture aeration is also crucial for the composition of the cell fatty acid. The final results showed that few differences were observed between NIC and MIC estimations with respect to cells pre-cultured in the presence or absence of oxygen.

Pub.: 21 Mar '15, Pinned: 08 Nov '16

Research Paper

The family variable in the French and Italian wine sector

Abstract: EuroMed Journal of Business, Volume 11, Issue 1, May 2016. Purpose The objective of the research was to highlight the differences in terms of economic and financial performance, between family firms (FFs) and non-family firms (NFFs) in the wine sector in Italy and France, where this sector is one of the most representative national economic activities. Design/methodology/approach This study is based on a sample of Italian and France companies operating in the wine sector. The sample, including medium and large firms, includes 288 FFs and 302 NFFs, for a total of 590 firms. Amadeus database represents the data source. According to Astrachan and Kolenko (1994), a firm is classified as a family firm if family had to own over 50% of the business in a private company or more than 10% of a public company. Findings This study confirms that the family variable is relevant to achieve good economic and financial performance, and endow firms with different features. In terms of economic performance, FFs both in Italy and France outperform in terms of ROE and ROA, though only Italian NFFs outperform in EBIT. In terms of financial performance, both in Italy and France NFFs outperform FFs in current ratio and liquidity ratio, while FFs outperform in solvency ratio. Research limitations/implications Limitations of the study concern the method adopted, as it could be integrated with some econometrical models. The implications of our paper are relevant for families and regulatory bodies because it helps them to better understand the effects of governance on economic and financial performance. Moreover, the findings of the study can influence the decision-making process of investors in order to identify the long-term outperformers listed on a stock exchange. Originality/value This study contributes to the literature on family businesses phenomenon on wine sector, which represents one of the most representative of the economy of several countries and in which family businesses are widespread.

Pub.: 11 Mar '16, Pinned: 08 Nov '16

Research Paper

Making wine and making successful wineries: resource development in new ventures

Abstract: International Journal of Organizational Analysis, Volume 24, Issue 1, March 2016. Purpose Most research on new organizations drawing on resource-based theory examines firms in discrete development stages with resources that already exist. This paper articulates a broader view of changing resource requirements over the life of new organizations. We propose four phases of resources development, arguing that new resources and capabilities must develop as new strategic challenges emerge. We identify salient resources in these phases and find that internal resource development is context-dependent, interacting with the external stage of industry development. Design/methodology/approach After developing our theoretical model we use an exploratory qualitative study involving extensive case studies of new ventures in the wine industry. Key personnel at a sample of firms were interviewed supplemented with secondary data from published reports. Findings We find that a linear stage development model for new organizational ventures is inappropriate. The various combinations of early/later new ventures in a formative/developed industry suggest that some may proceed rapidly in a linear fashion through phases of development, while others may find progress slow, difficult, stalled, or occasionally regressive. a combination of resources developed simultaneously in a non-linear pattern appears to be critical to the success of new ventures. In other words, combinations must evolve as the strategic challenges evolve thus bringing an important contextual view to the examination of dynamic resource development efforts for new organizations. Attempts to focus in a piecemeal fashion on individual aspects of resource development, without accounting for resource interactions at a systemic level or the nature of the strategic demands, is likely to leave researchers and practitioners with incomplete insights. Originality/value Existing studies have failed to grasp the dynamic and interactive process of resource development as organizations evolve in a new industry setting. Our model provides a heuristic device for conceptualizing these changes.

Pub.: 29 Jan '16, Pinned: 08 Nov '16

Research Paper

Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model ☆

Abstract: Chinese rice wine making is a typical simultaneous saccharification and fermentation (SSF) process. During the fermentation process, temperature is one of the key parameters which decide the quality of Chinese rice wine. To optimize the SSF process for Chinese rice wine brewing, the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model. The kinetic parameters as a function of temperature were evaluated using the software Origin8.0. Combing these functions with the mathematical model, an appropriate form of the model equations for the SSF considering the effects of temperature were developed. The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model. The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm. The optimum temperature profile began at a low temperature of 26 °C up to 30 h. The operating temperature increased rapidly to 31.9 °C, and then decreased slowly to 18 °C at 65 h. Thereafter, the temperature was maintained at 18 °C until the end of fermentation. A maximum ethanol production of 89.3 g/L was attained. Conceivably, our model would facilitate the improvement of Chinese rice wine production at the industrial scale.

Pub.: 31 May '16, Pinned: 08 Nov '16