8C Volatile Compounds and Wine Aging 307
The type of oak wood used is also important, since the volatiles released by
different types of oak usually differ hence so do the resulting wines. Tasters tend to
prefer a balance between the “oak” aromas ordinarily produced by the oak lactones
and the grape variety’s own fruity aromas (P ́erez-Coello et al. 2000b).
On the other hand, using toasted oak chips has been reported to cancel out the
varietal attributes by increasing the wood attributes and adding toasted and smoky
aromas that can mask the white wines fruity aromas (Guchu et al. 2006b).
Chip size, wood pieces vs wood chips, and the time the wood is in contact with
the wine are all major factors affecting the volatiles released by the wood and hence
the final volatiles content and the sensory characteristics of the wine. Barrel-aged
wines were discriminated from oak chips treated wines from the same variety on the
basis of their syringaldehyde and eugenol contents, while wine treated with small
and big chips were discriminated on the basis of guaiacol (Arapitsas et al. 2004).
Wine treated with oak chips matures quickly, and more phenolic compounds can
be extracted from wood chips than from oak staves and oak barrel aging (Alamo-
Sanza et al. 2004).
Comparing the aging of a Merlot wine in contact with different types of French
oak chips and the barrel aging of the same wine demonstrated that the wood chips
released more oak lactones, furfural, and eugenol than new barrels. On the other
hand, oak chips aging yielded more uniformwines with fewer differences according
to oak origin (Frangipane et al. 2007).
Adding small doses of oxygen (microoxygenation) while wines are in contact
with oak chips can yield wines that are much like red wines that have been aged in
the barrel by producing changes similar to those brought about by the oxidation that
takes place during barrel aging. More research on these treatments and their effect
on wine aroma is needed.
The complexity of the oak aged wine aroma justifies the numerous studies that
have been realised on the different aspects considered in this review. Factors that
affect volatile composition of the oak woods and their treatments, the shelf-life of
the barrels, and the chemical reactions that happens into the barrel or those induced
by microorganisms. The sensory impact of the compounds ceded by the wood and
their synergist effects with those of the wine make difficult the standardisation of an
oak aged wine. On the other hand, the possibility of using oak wood chips or staves
as an alternative to oak barrel aging, together with their effectiveness for obtaining
a quality product, are aspects that will have to be developed in the near future.
References
Alamo-Sanza, M., Nevares-Dom ́ınguez, I., & Garc ́ıa-Merino, S. (2004). Influence of different
aging systems and oak woods on aged wine color and anthocyanin composition.Eur. Food
Res. Technol., 219, 124–132.
Aleixandre, J. L., Padilla, A. I., Navarro, L. L., Suira, A., Garc ́ıa,M.J.,&Alvarez, I. (2003). ́
Optimization of making barrel-fermented dry muscatel wines.J. Agric. Food Chem., 51,
1889–1893.