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p r a c t i c a l w i n e r y & v i n e ya r d O c t O B e r 2 0 1 4 65 w i n e M A K i n G ceived in the wines with significant levels of furanic compounds (Table II). Table II: Pearson correlations between chemical and sensory data. Marked corre- lations are significant at p <0.05. NS = not significant difference; *, **, *** Significant differences at 5, 1 and 0.1% respectively On the other hand, wines with a high content of guaiacol, methyl-guaiacol, syringol and syringaldeyde were char- acterized as less astringent. This obser- vation is logical as toasting decreases ellagitannins and increases the con- centration of volatile compounds that enhance the oak aroma. Judges perceived the sweetness per- ception more intensely in wines with higher levels of lactones, eugenol and vanillin compounds. The levels of these compounds are correlated positively with the perceived intensity of vanilla aroma (Table II). Vanillin is the principal marker of vanilla smell. Lactones can be regarded as direct contributors and/or possible enhancers of this descriptor. Overall woody character is positively correlated to guaiacol, methyl-guaiacol, eugenol, syringaldeyde, lactones and vanillin levels, which is reasonable since oak evaluation is complex and influ- enced by the presence of various odor- active wood extractives. 6 For example, whisky lactone is an attri- bute that accounts for a woody and coco- nut character, while high concentrations of this compound are associated with wine with an intense vanilla perfume. Perceived spicy intensity is closely related to eugenol content, which is logical, since pure eugenol is described as clove-like. In our experiment, it is also linked positively to the presence of other odor- ous chemicals such as lactones, vanillin and methyl guaiacol, suggesting that in a complex medium such as wine the above volatile compound values may influence spicy aroma by means of additive or synergistic effects. An important reduc- tion in spicy and vanilla aroma occurs in wine with a significant level of furfural. Conclusions The results have shown that each oak stave adds unique and special charac- teristics. Each sample shows a different ability to extract the compounds (vola- tile and non-volatile). Different rates of extraction have been observed, depend- ing mainly on the origin of the com- pounds in the wood (toasting or present in natural wood) and on the watering process during toasting. These differ- ences were reflected by perceived sen- sory differences. In general, volatile phenols such as eugenol and guaiacol, along with aldey- des, phenols (vanillin) and lactones, showed an increasing tendency with longer maceration time. Ellagitannins are extracted faster during the first three months; after six months a decrease is observed. Evolu on of aromas Evolu on of taste (sweetness and bi erness) and sensa on (astringency) 6 LT MT MT+ Noise e Special 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 5 4 3 2 1 0 5 4 3 2 1 0 Vanilla Woody Spicy Intensity Intensity Sweetness Astringency Bi erness LT MT MT+ Noise e Special Evolu on of aromas Evolu on of taste (sweetness and bi erness) and sensa on (astringency) 6 LT MT MT+ Noise e Special 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 6 9 12 5 4 3 2 1 0 5 4 3 2 1 0 Vanilla Woody Spicy Intensity Intensity Sweetness Astringency Bi erness LT MT MT+ Noise e Special Figure 3. Sensory evaluation of wine treated with different winewoods during different contact times (6, 9, 12 months).