8C Volatile Compounds and Wine Aging 301
Chardonnay wines in contact with Hungarian and Russian oak wood with low
oak lactone contents scored well for oak wood sensory attributes. GC-sniffing anal-
ysis of these woods concluded that such other components as eugenol and thecis
andtransisomers of isoeugenol, together with guaiacol and its derivatives, also
contributed to the “spicy”, “clove”, “cinnamon”, and “woody/oaky” aromas. Oak
lactones, on the other hand, elicited theodour descriptors “sweet”, “vanilla”, and
“oaky” (D ́ıaz-Maroto et al. 2008).
Table 8C.1 summarizes the oak wood components that are significant from a sen-
sory standpoint together with the corresponding sensory descriptors as determined
by GC-sniffing of different oak extracts, with an indication of the effect of toasting
on the relative odour intensity of these components. The table shows furfural and
its derivatives, guaiacol, cyclotene, and phenylacetaldehydeto be the components
having toasting-related odourdescriptors. These components together with vanillin,
eugenol and derivatives increased their odour intensity during toasting.
In contrast, odour intensity of other components related to “off flavours” (“herbal”,
“sawdust”, “greasy”, and “cucumber”) canbe seen to decrease with toasting. The
same happened with the intensity of fruity and floral aromas of linalool oxide, -
damascenone, or 2-phenylethanol, and the oak lactones odour descriptors.
Figure 8C.1 uses a spider plot to compare the sensory scores awarded to the
Chardonnay wines in contact with American and Hungarian toasted wood chips.
It shows that, despite differences in oak lactone content, the wood attributes were
similar in these wines. Toasting increase the similarities between wines treated
with oak wood of different origins, masking the natural fruity and floral attributes
of Chardonnay wine. None of the “off flavours” in the woods used for macera-
tion that were detected by sniffing (Table 8C.1) were later detected in the wines,
which suggests either that concentrations of the components responsible were
below the detection thresholds or that these aromas were masked by other stronger
attributes.
Spillman et al. (2004b) studied the sensoryeffects of the oak wood components in
wines made from Chardonnay and Cabernet Sauvignon grapes and recorded differ-
ent effects in each type of wine. The “smoky” attribute was most highly correlated
with the wood components in the Chardonnay wines, but this descriptor was not
correlated with any of the components in the Cabernet Sauvignon wines. On the
other hand, the Cabernet Sauvignon wines tended to have highly complex aroma
profiles, and a number of the components present in these wines (cisoak lactones,
4-methylguaiacol, vanillin, eugenol, furfural derivatives) were positively correlated
with the “vanilla”, “coffee”, and “dark chocolate”descriptors.
Similarly, such flaws as “green apple” and “earthy” aromas were negatively
correlated with oak wood components, and this attests to the ability of these oak
wood components to mask vegetative aromas and “off flavours” in wine. How-
ever, other authors found that the descriptor “wood-vanilla-cinnamon”, due to
oak extracted compounds in Spanish red wines, was negatively influenced by the
presence of 4-ethylphenol, 4-ethylguaiacol and phenylacetaldehyde (Aznar et al.
2003).