American white oak

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. 

Quercus alba, also known as American white oak, and two European species, Quercus roburh. and Quercuspetraea Liebl, the former also known as pedunculate oak and the latter as sessile oak, are the species most frequently used in coopering. 

That not all of the xylans of wood are homogeneous polymers of anhydro-D-xylose units has been shown by the classical studies of O Dwyer (1923 to 1940) on hemicelluloses of American white oak. O Dwyer prepared a hemi-cellulose fraction from water-extracted, oakwood sawdust by extraction for two days with 4% aqueous sodium hydroxide solution. The polysaccharide material was obtained, after acidification, by the addition of ethanol. The product ([a]n —75° in 1 % sodium hydroxide), contained 70% of pentosan, and yielded n-xylose, n-maiinose, n-galactose, and L-arabinose on hydrolysis. 

The twelve new and twelve used barrels used in this experiment were made of American white oak (Quercus alba, fine grain) or French oak (Quercus petraea from the Allier forest in France), and were obtained from the same cooperage firm in Spain with the same specifications (medium toast level). The used barrels had been used three times for the aging of Monastrell wine and they were sanitatied before use by burning sulphur inside. The following barrels were used in the experiment 220 liter French oak barrel (3 new barrels and 3 used barrels) 220 liter American oak barrels (3 new barrels and 3 used barrels) 500 liter American oak barrels (3 new barrels and 3 used barrels) and 1000 liter American oak barrels (3 new barrels and 3 used barrels). 

In the USA, the dominant species is American white oak (Quercus alba). This species has a low phenol content and a high concentration of aromatic substances, especially methyl-octalactone, which strongly affect the flavor of wine during aging (Table 13.17). 

American white oak (Quercus alba) is very fragrant. It is rarely used for premium white winemaking, as excessive concentrations of P-methyl-j/-octalactone are apt to be released, totally masking the wine s character. American oak is recommended for rapidly oaking ordinary white wine. 

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