Ageing of wine

Jurd, L., Review of polyphenol condensation reactions and their possible occurrence in the aging of wines. Am. J. Enol. Vitic. 20, 197, 1969. 

On the one hand, wine is a typical preserved food because its shelf life is affected by time and temperature during storage. Conversely, many wines are considerably improved by moderate storage after packaging. Much has been written about the development of bottle bouquet during the aging of wine in glass (13, 14, 15, 16, 17). 

Singleton, V. L., Aging of Wines and Other Spiritous Products, Accelera-... 

B Ayestaran, C Ancin, M Corroza, J Garrido. Changes in free amino acid concentration during stabilization and aging of wines derived from garnacha and viura musts clarified by static sedimentation. Food Control 7 157-163, 1996. 

Heterocycles formed upon aging of wines and oxidation processes... 

Chatonnet, P. and Dubourdieu, D. (1998). Comparative study of the characteristics of American white oak ("Quercus alba") and European oak ("Quercus petraea and Q. robur") for production of barrels used in barrel aging of wines. ]. Int. Sci. Vigne Vin. 32, 99-104. 

Morales, M. L., Benitez, B., and Troncoso, A. M. (2004). Accelerated aging of wine vinegars with oak chips Evaluation of wood flavour compounds. Food Chem. 88, 305-315. 

Aging of wine implies changes in flavor and bouquet believed attributable to slow oxidation, particularly so during aging in wood with a relationship of wood surface area to volume of wine. In a small oak cask or barrel, there is more wood surface area per gallon of wine than in a larger cask or tank. 

Moreno-Arribas, V., Pueyo, E., Polo, M.C. and Martin-Alvarez, PJ. (1998b). Changes in the amino acid composition of the diffeent nitrogenous fractions during the aging of wine with yeast. J. Agric. Food Chem., 70, 309-317. 

The biological aging of wines has aroused increasing interest in recent years, as reflected in the large number of papers on this topic over the last decade. Biological aging in wine is carried out by flor yeasts. Once alcoholic fermentation has finished, some Saccharomyces cerevisiae yeast races present in wine switch from a fermentative metabolism to an oxidative (respiratory metabolism) and spontaneously form a biofllm called flor on the wine surface. Wine under flor is subject to special conditions by effect of oxidative metabolism by yeasts and of the reductive medium established as they consume oxygen present in the wine. These conditions facilitate... 

The nitrogen requirements of flor yeasts are supplied largely by L-proline, which they metabolize under aerobic conditions as the biological aging of wines. L-Proline is converted into glutamic acid, which favours growth and persistence of the flor fllm (Botella et al. 1990). 

Metabolite concentrations in wine depend on the particular aging conditions, number of rows in the criaderas and solera system, number of rocios and volume extracted for bottles per year, ratio area of the flor film to volume of wine, climatic conditions of the cellar (temperature and relative humidity) and alcoholic concentration, in addition to the particular flor yeasts present. Below are described the most common changes observed during the biological aging of wine, whether related to yeast metabolism or otherwise. 

Acetaldehyde takes part in a number of reactions during the biological aging of wine one of the most important of which is the formation of 1,1-diethoxyethane. This acetal results from the combination of acetaldehyde and ethanol. Its concentration, which is closely related to those of the parent compounds, can easily exceed 100 mg/L (Munoz et al. 2005). Also, 1,1-diethoxyethane is the only acetal contributing to the aroma of wine (Etidvant 1991). 

Oak wood barrel aging of wine from the end of fermentation to bottling is a common practice at wineries, chiefly for red wines but sometimes also for white wines. 

Arapitsas, R, Antonopoulos, A., Stefanou, E., Dourtoglou, V. G. (2004). Artificial aging of wines using oak chips. Food Chem., 86, 563-570. 

Perez-Coello, M. S., Sanz, J., Cabezudo, M. D. (1998). Gas chromatographic-mass spectromet-ric analysis of volatile compounds in oak wood used for ageing of wines and spirits. Chro-matographia, 47, 427 32. 

Finally, some of the most powerful wine aroma compounds take part in reversible interactions which evolve during wine aging and that can be reversed, at least in part, when the wine takes contact with air. These aspects have not yet been studied in depth, but it is well known that carbonyls form reversible associations with sulfur dioxide and that mercaptans take part in complex redox equilibria. These molecules involved in interactions or in redox equilibria are the most likely cause of the aromatic changes noted during the aging of wine or after the bottle is opened. 

Cantos et al. 2003 Gambuti et al. 2004). It is also influenced by yeast enzymatic activities, in particular those of isomerase and glucosidase (Jeandet et al. 1994). Equally, activities of lactic acid bacteria, which are responsible for malolactic fermentation (Hernandez et al. 2007), can also affect stilbene content in wine (Poussier et al. 2003). Aging of wine appears to have no important influence on the concentration of stilbenes (Jeandet et al. 1995). 

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