Wine aging volatile

Fernandez de Simon B, Cadahia E and Mocha J. 2003. Volatile compounds in a Spanish red wine aged in barrels made of Spanish, French, and American oak wood. J Agric Food Chem 51 (26) 7671— 7678. 

Total acidity. This acidity, expressed as tartaric acid, varies from 4-5 to 15-X6 grams per litre. Wines rich in alcohol are relatively less acid than those of low alcohol content, owing to precipitation of the potassium bitartrate by the alcohol. Further, the total acidity of a wine diminishes as the wine ages, in consequence of precipitation Of this salt and also Of the tannin and likewise of decomposition of the malic acid into lactic acid Of one-half the equivalent acidity. On the other hand, the total acidity may be increased indirectly as a result of certain diseases of the wine which increase the volatile acidity. 

Evolution of volatile compounds during Madeira wine aging... 

FIGURE 7.9 Evolution of some chemical families of volatile compounds during Madeira wine aging (adapted from Camara, 2004). 

Perez-Coello, M. S. and Diaz-Maroto, M. C. (2009). Volatile compounds and wine aging. In "Wine Chemistry and Biochemistry", (M. V. Moreno-Arribas and M. C. Polo, Eds). Springer, New York, USA. 

Other volatile compounds present in oak wood can transmit unpleasant aromas to the wine, such as the sawdust aroma of dry wood that is perceptible in some wines aged in new barrels. The substances that cause these aromas have been identified in both American and European oak wood, for instance, ( )-2-nonenal, 3-octen-l-one, ( )-2-octenal, and 1-decanal. Their connection with the sawdust aroma has been established by olfactometry, and they have been identified in wines suffering from this flaw, though toasting the wood (Chatonnet and Dubourdieu 1998). 

In terms of its volatile composition, Spanish oak is comparable to French oak of the same species. There are also two native species, Q. pyrenaica and Q. faginea, which have amounts of the oak lactones, vanillin, and eugenol that are statistically comparable to those in French oak, though wines aged in Q. faginea barrels have received particularly poor ratings by taste panels, earning low scores for the characteristic oak wood sensory attributes (Ferndndez de Simon et al. 2003,2006 Cadahfa et al. 2003). 

Jimenez Moreno, N., Ancin Azpilicueta, C. (2007). Binding of oak volatile compounds by wine lees during simulation of wine ageing. Lebens. Wissen. Technol, 40, 619-624. 

Table II. Incidence of the origin of wood and intensity of toasting on the volatile compounds of a white wine aged nine months in new oak barrels...

Effect of wine ageing on monoterpene composition. Several studies have been made in which alterations in monoterpene distribution in wines over time or with increases in temperature were recorded (84-89). The effect on wine flavor of prolonged ageing or exposure to elevated temperatures is a loss of fruit bouquet. By contrast, brief heating of juices of aromatic grapes can enhance the fruit flavor by increasing the concentration of free volatile monoterpenes through hydrolysis of precursors. 

Some phenolic acids like caffeic acid, p-coumaric acid and ferulic acid can act as precursors of volatile phenols, which could contribute positively to wine aroma, when they are present at low concentrations associated descriptors are smoky, dove-like and leather (Table 1). Yeasts can conduct the decarboxylation of phenolic adds to volatile phenols, as well as esterase activities present in enzymatic preparations used in winemaking. During wine storage and ageing, volatile phenols may be further transformed. 

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