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1 SEGUIN-MOREAU cooperage (Merpins, F-16103 COGNAC) at
Bordeaux Faculty of Enology, 33405 Talence Cedex, France
2 Bordeaux
II University, 351, Cours de la Libération, F-33405 Talence Cedex, France.
Among the many species of the genus Quercus, only a few are of major technological interest for cooperage.
In this work, the main structural and physical-chemical characteristics likely to affect the watertightness of the
barrels and the quality of wines stored in oak wood were investigated for three different species in the
Erythrobalanus section: American white oak (Quercus alba), sessile oak (Quercus petraea), and pedunculate
oak (Quercus robur). Scanning electron microscope images showed that the fact that it is possible to saw-cut
American white oak staves, without risking loss of watertightness, is principally due to the special structure of
the thyllae in the heart wood of this species. On the other hand, European oak must always be split to avoid
rupturing the vessels, as the thyllae of these species do not provide an adequate barrier against liquid
seepage. Whereas European pedunculate oak has high quantities of extractable ellagic tannins, sessile oak
releases much smaller quantities of polyphenols, and white oak even less. The American species have a
greater aromatic potential than European oak due to their high content of cis/trans isomers of
-methyl-
-octalactone. American white oak is easily identified by the low quantity of extractable polyphenols, the high
methyl-octalactone content and the presence of two isomers of 3-oxo-retro-
-ionol. European sessile oak and
American white oak are perfectly suitable for aging fine wine. Pedunculate oak, with its low aromatic potential
and high ellagitannin content, is best suited to aging spirits. The quantity of extractable methyl-octalactones in
American white oak is sometimes excessive and would be likely to have a negative influence on the wine's
aroma. Proper control of toasting operations in barrel-making could facilitate the use of this type of oak, by
modeling the release of volatile and odorous substances from the wood.
Key words: Quercus petraea, Quercus robur, Quercus alba, ultrastructure, chemical composition
Submitted on October 21, 1996
This article has been cited by other articles:
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E. Cadahia, B. F. de Simon, R. Vallejo, M. Sanz, and M. Broto Volatile Compound Evolution in Spanish Oak Wood (Quercus petraea and Quercus pyrenaica) during Natural Seasoning Am. J. Enol. Vitic., June 1, 2007; 58(2): 163 - 172. [Abstract] [Full Text] [PDF] |
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