Wine Chemistry and Biochemistry

8C Volatile Compounds and Wine Aging 303

Wine control

Wine macerated with toasted Hungarian oak chips

Wine macerated with toasted American oak chips

0

1

2

3

4

5

6

7

8

Fresh

Green apple

Floral

Banana

Buttery

Pineapple

Melon Fruity (peach)

Ripe fruit

Clove

Woody

(oaky)

Vanilla

Toasty

(smoke)

Fig. 8C.1Sensory characteristics of a Chardonnay wine and the same wine macerated for 24 days
with toasted Hungarian and American oak chips

8C.4 Changes in the Wine Volatile Composition During

Oak-Barrel Aging

The release of volatiles from the wood into the wine during the barrel aging of

wine is regulated by diffusion kinetics (Rous and Alderson 1983). As a general

rule, extraction of volatiles is highest at the beginning of aging and then gradually

tapers off with aging time and barrel age (Puech 1987; Towey and Waterhouse 1996;

G ́omez-Plaza et al. 2004). Small amounts of such compounds as guaiacol, furfural,

and 5-methylfurfural are present in winesaged in previously used barrels. Other

compounds like eugenol and 4-methylguaiacol are not detectable in these wines,

but on the other hand concentrations of oak lactones increased in the second year of

barrel use and then begin to fall back in the third year (Towey and Waterhouse 1996).

One recent study showed that extraction of volatile substances from the wood

dropped off sharply after 12 months ofaging, though there was high variability

between wines, highlighting the influence of such major oenological factors as the

tartaric acid content and the potassium content and also the SO 2 concentration in

the wines, since SO 2 can combine with certain furanic derivatives and phenolic

aldehydes (Anc ́ın et al. 2004; Ortega-Heras et al. 2007).

Nevertheless, aging time and barrel age should not be looked at separately,

because differences in the release of volatiles have been shown to be closely linked

to barrel age only for short aging times of six to nine months, with the effect of barrel

age tailing off considerably for agingtimes longer than 12 months (Garde-Cerd ́an

and Anc ́ın-Azpilicueta 2006).