Q. robur

Variations within a tree may be large. In one example from Q. robur, the tannin of the bark was 10.9%, sapwood 1.0%, and heartwood 7.7% at the periphery, 6.6% intermediate, and 6.6% at the center, all at the base of the tree which was 50 cm in diameter and 90 years old (31). At the top of the same trunk (34-cm diameter, 71 years) the same respective tissues had tannin contents of 5.7, 0.8, 5.3, 4.6, and 4.7%. This pattern of higher extractable tannin in the heartwood nearest the sapwood and lower near the pith, higher as the tree gets older, and higher in the base of the tree than the top is general (21). 

The geographical range of Q. robur includes essentially all of that of Q. sessilis but extends further north in Scandinavia, much further east into Russia (to the Urals), and further south in Turkey, Soviet Georgia, and Portugal (31, 39). They are found together over the rest of Europe from the British Isles to beyond Warsaw and nearly to Odessa, and from Scandinavia to the Balkans, Italy, and northern Spain (31, 39). Since... 

From the considerations outlined, it appears one can usefully divide oak species having a reputation for high quality wine or brandy barrels into only two groups North American oak derived from Q. alba and related species and European oak derived from Q. sessilis and Q. robur. Woods derived from other oak species seem either to be inferior or to have been insufficiently tested to demonstrate their qualities. These two groups, North American and European, have sufficiently different extractives that it is often possible for an experienced taster to state which was used for wine or brandy storage. Within each group, however, the flavor... 

Chatonet, P. and Dubourdieu, D. (1998). Comparative study of the characteristics of American white oak (Quercus alba) and European oak (Querqus petraea and Q. robur) for production of barrels used in barrel aging of wines. Am. J. Enol. Vitic. 30, 61. 

In a study of Pinot Noir wines aged in different types of oak wood, the wines that earned the highest scores for the attributes woody , toasted , vanilla and coconut contained the highest quantities of the cis oak lactone isomer (Sauvageot and Feuillat 1999). This component exerts the greatest sensory effect in wines aged in oak wood, and the cis isomer is present in quantities greater than the detection threshold even in species low in lactones, like Q. robur (Dtaz-Maroto et al. 2004). 

Figure 3. Radial disuibutions of Cd in stem wood of an oak tree Q. robur) from Bielefeld, Germany. The tree was sampled twice with an interval of 10 years. Wood samples were taken at breast height with an increment borer. Arrows indieate the position of the border between sapwood and heartwood at the sampling dates. After Hagemeyer (1995).

Vivas N. (1997) Recherches sur la qualite du chene franfais de tonnellerie (Q. petraea L., Q. robur L.) et sur les mficanismes d oxydor6duction des vins rouges au cours de leur 61evage en barriques. Thhse Doctorat, Universite de Bordeaux II. 

Sauvageot, E, Feuillat, F. (1999). The influence of oak wood (Quercus robur L., Q. petraea Liebl.) on the flavor of Burgundy Pinot noir. An examination of variation among individual trees. Am. J. Enol. TechnoL, 50, 447 55. 

For the production of oak barrels in Europe wood of the English oak (Quercus robur) or of the Sessile oak (Q.petraea) and in the USA the wood of the white oak (Q. alba) are used. In addition to insoluble polymers (cellulose, hemicelluloses and lignin), oak wood contains about 10% of phenolic compounds in dry matter, the predominant part of which are ellagotannins. 

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