Congener Development in Bourbon Whisky Matured at Various Proofs for Twelve Years

Abstract

The color intensity and congener concentration of bourbon whiskies matured for 12 years decreased as the entry proof increased from 109 to 155°, except for fusel oil content which remained approximately constant. The average annual cumulative evaporation loss rates, in per cent of original proof gallons/year, were approximately the same at all 6 proofs, i.e., 3.0%/year or 3 6% for the 12 year period. The relative rates of formation of total barrel-derived material, a newly proposed parameter defined as the sum of the increase in volatiles and nonvolatiles in an aged product, were quite similar for comparable time intervals regardless of entry proof. There was greater variation among the relative rates of formation of individual congeners at the different entry proofs. Although all congeners except esters attained at least 5 0% of their ultimate (twelfth year) value during the first 4 years, it appears that appreciable congener development continues at least through 12 years. Esters developed linearly over the 12 year period.

Comparative Evaluation of Brandy de Jerez Aged in American Oak Barrels with Different Times of Use

“…Except for furfural, all of the above mentioned compounds could not be detected in the initial wine spirit, since they are provided by the wood or the wine in the case of seasoned barrels, and they are easily and generally found in brandies aged in wood [ 4 , 17 , 19 , 20 , 21 , 44 ]. When wood is used for the first time, a large amount of these compounds are transferred into the liquid [ 45 ]. Therefore, the brandy held in New barrels contains a larger concentration of them than those held in Used barrels , because these wood compounds had already been extracted in large quantities during the previous use.…”

“…Thus, when the brandy was aged in new oak barrels, the samples were less vinous and balanced and presented higher notes of vanilla, toasted/caramel and oak than the others brandies. When wood is used for the first time, a large amount of phenolic compounds are transferred into the liquid [ 45 ], as can be seen in Section 3.2 . It should be highlighted that the 4 tasters associated the highest flavor notes of oak, that had been attributed to the brandies aged in New Barrels , with astringent sensations and ‘aggressiveness’.…”

Use of Alternative Wood for the Ageing of Brandy de Jerez

“…This highlights the relevance of the size of the barrel during the extraction process, in particular, the surface/volume ratio, and as a result, a higher concentration in the distillates for the same aging time [38]. We could think that these values are due to the fact that the studied samples are taken at 6-week aging, and due to this, the extraction process is in its first stage [39]. However, it is important to remember that the barrels used for this study have been previously seasoned with Oloroso wine; i.e., before having the distillate, they contained wine, and as a result, the high extraction stage already took place during the previous seasoning stage.…”

Variation of the Flavour and Extractives of European Oak Wood from Two French Forests

“…Many physical and chemical properties of the wood may influence the process of maturation, but most previous studies have focused on the direct or indirect effects of heartwood extractives. These extractives may be influenced by factors such as the oak species, the method of wood seasoning and cask construction and later treatments or uses of the finished cask, as reviewed by Mosedale 1995. Previous studies (Guymon and Crowell 1970;Baldwin and Andreasen 1974;Singleton 1974;Rous and Alderson 1983,;Puech 1984) reported differences in the * To whom correspondence should be addressed. levels of many extractives, including tannins, between American white oak (predominantly Quercus alba L) and the European oaks Q robur L and Q petraea (Matt).…”