1. Introduction Materials and methods
10th In Vino Analytica Scientia Symposium
Volatile compounds in the Quercus humboldtii (Colombian oak) and in the wines aged with them, respect to traditional oak woods used in cooperage
A.M. Martínez-Gila,1* G. Gutiérrez-Gamboa1, Y. Moreno-Simunovic1, I. Nevaresa, M. Alamo-Sanzaa
aGrupo UVaMOX, E.T.S. Ingenierías Agrarias, Universidad de Valladolid, España. 1Centro Tecnológico de la Vid y el Vino, Facultad de Ciencias Agrarias, Universidad de Talca, Talca, Chile. *
Introduction
Materials and methods
Aroma, color and taste of wines are remarkable quality factors, and them can be greatly modified by oak contact. Currently, ageing habits for wines are changing towards the use of newer oak barrels, and the demand for oak in oenology is increasing. Thus, it is necessary to search new sources of wood, for suppling coopers with an alternative to traditional woods. Quercus humboldtii from Colombia, currently used for some alcoholic beverages (Rum or Brandy), could be an alternative source. Limited information is available about this species.
To know if this new oak source has an oenological interest, we studied the volatile composition of Q. humboldtii toasted wood and the wines ageing with chips from this specie, comparing it with respect to the traditional oak woods used in cooperage and the wines ageing with them.
To carry out this study four different oak woods (origin and/or species) were used in this trial: Quercus sessilis (French and Rumanian), Q. alba (USA) and Q. humboldtii (Colombian). All the woods were toasted at the same time by the cooperage Tonelería Nacional Chile LTDA..
Chips of these toasted woods were put in contact with Carménère wines in a 3 g/l dose during 90 days
Volatile compounds of toasted wood and wines aged with oak chips were analyzed by SPE-GC-MS.
Sensorial analysis was carried out after 90 days in contact with the different woods and 5 months in bottle by expert judges.
Results and discussion
Q. humboldtii toasted wood exhibited higher concentrations of several volatile compounds such as 5-methylfurfural, guaiacol, isoeugenol and syringol than others oaks, but lower concentration of furfural and trans-3-Methyl-4-octanolide. However, compounds such as vanillin, eugenol, cis-3-Methyl-4-octanolide among others did not present significant differences to traditional woods.
Wine treated with this oak presented a similar relation of some of the above-mentioned compounds found in oak wood compared to the wines ageing with chips from traditional oak wood. Wines treated with toasted chips from Q. humboldtii wood showed higher guaiacol, isoeugenol and syringol concentrations and lower furfural and trans and cis-3-Methyl-4-octanolide content.
Figure 2. Sensorial analysis of Carménère wines ageing with different specie or origin chips during three months
The sensory analysis results are in agreement with the chemical analysis. Wine ageing with Colombian oak was one that presented the higher smoky and lower coconut aroma notes.
There were no negative comments about this wine, moreover the rest of the attributes were similar to the wines ageing with traditional woods.
Conclusions
This oak presented the same compounds that the traditional woods and also the wines ageing with them, only quantitative differences existed.
Oak wood volatile composition from Q. humboldtii has particular attributes that allow it to differentiate from the Q. alba and Q. sessilis
This research has yielded useful results showing an interesting enological potential of Quercus humboldtii as a new species for coopering.
Figure 1. Volatile compounds in different woods (µg/g) and Carménère wines ageing with this oak chips during three months (µg/l)
ACKNOWLEDGEMENTS
This work was funded by Grant Nº from Fondecyt, Chile and it had the collaboration of Tonelería Nacional LTDA, Santiago de Chile and J.Bouchon wine cellar.