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Oregon Oak: Quercus garryana

Quality starts in the forest, where only trees that meet our demanding specification are selected. The wood is then hand split in the traditional French style and air-dried for a minimum of three years.

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Three Year Air-dried Orgon Oak Stavs

The ample rains of Western Oregon help soften the tannins and accent the natural sweetness of the oak. Similar climatic conditions that allow the production of viniferous grape varieties also yield oaks that are similar to those of France. Oregon Oak is frequently equated with French Oak given its comparable flavor profile.

Supporting Technical Data:

To download Oregon Oak data and spider graphs of medium toast and medium plus toast Oregon Oak, please click here.




An Examination of a sample of Quercus garryana (Oregon Oak)

 

Authors: James S. Swan, Stewart P. Hewlett

 

Summary

 

One sample piece of Oregon oak (Q. garryana) was provided for advice regarding its suitability for wine barrel cooperage.  The sample was recently cut but had dried out substantially during transport to the UK.  Accordingly it was considered as a slightly seasoned sample, in fact a seasoned age of 2 months was assumed.  The sample was examined in the respect of its chemistry and for its physical suitability.

 

The results were interesting.  As a native of the USA it has many of the characteristics of European oak, but, as a result of these characteristics it may prove difficult to produce good tight cooperage.  Some aspects of the chemistry were also similar to European oak.  The levels of tannins were very much higher in the Oregon oak compared to American White oak suggesting that when, and if, it is very well seasoned the resulting wine might benefit substantially rather like one of the features of French oak.  However if these high levels of tannins are not efficiently broken down during seasoning the finished wine might be bitter and astringent.  Analysis also suggest that Q. garryana is less prone to thermal or fungal breakdown than American White oak.

 

The radial rays of Q. garryana were more variable in size than American White oak and tend to show considerable discontinuity.  The annual rings were very diffuse sometimes with little obvious sign of transition from one ring to another; the straightness of the grain was reasonably good but was less so than American white oak. Tyloses structure of the wood was also reminiscent of European oak being less well formed and thinner than American white.

 

This type of wood, if being used in cooperage would require, in the main, to be cleaved rather than quartersawn if leakage problems were to be avoided.  It is strongly recommended that if barrel construction with Q. garryana is to be considered the wood should be well seasoned and its chemistry should be examined for suitability before barrel construction begins.  The wood should be handled in the manner used for European oak rather than American oak i.e. the wood should be cleaved, attention to the straightness of the grain should be watched carefully and stave thickness should be greater.

 

 

Comparison of the Chemistry of Q. garryana with American White Oak

 

The sample of Q. garryana was analyzed in respect of some 40 extractives which occur in oak heartwood and are known to occur and influence the flavor of oak aged wines.  Table 1 below shows results for the13 most abundant and well known of these.  Data for American White oak is shown for comparison.  The latter results are average values for medium to slow growth Ozark White oak taken from a stow after 1-2 months of seasoning and with minimal drop in moisture content.

 

Table 1. Comparison of Extractives in Q. garryana with American White Oak*

 

Wood Extractives

Q. garryana

Q. alba

Gallic acid

94.3

679.68

Vescalagin ^a

13.1

0.84

Castalagin ^a

6.3

0.54

Hmf

16.7

126.88

Furfural

25.6

107.56

Vanillic acid

20.6

68.85

Syringic acid

21.2

35.14

Vanillin

16.1

15.2

Syringaldehyde

16.4

5.43

Scopoletin

0

27.62

Ellagic acid

936.5

428.88

Coniferaldehyde

0

10.77

Sinapaldehyde

11.7

6.78

 

  • * Results are in milligrams per kilogram of wood at as-is moisture content
  • ^a ? values are not in mG/Kg but are relative to each other

 

Interpretation of this data must be tempered with the comment that it refers, of course, to only one sample of the Oregon oak.  The most interesting results are those for the ellagitannins; vescalagin and castalagin and their breakdown products gallic and ellagic acids.  The ellagitannins themselves can produce high levels of astringency and bitterness, but if broken down to gallic and ellagic acids efficiently (as happens during air seasoning) they assist in the production of fragrance and delicacy in the finished wine.

 

The level of these compounds were very much higher in the Oregon oak compared to American White oak suggesting that when, and if, it is very well seasoned the resulting wine might benefit substantially rather like one of the features of French oak.  However, if these high levels of ellagitannins are not efficiently broken down during seasoning the finished wine might be bitter and astringent.

 

The hemicellulose breakdown products, furfural and hmf (5-hydroxy methyl furfural) were very much higher in the American White oak.  Whilst these compounds increase dramatically during the barrel toasting process the analysis suggest that Q. garryana is less prone to thermal or fungal breakdown than American White oak

 

Comparison of the Physical Aspects of Q. garryana

 

Examination of the sample provided showed distinct differences when compared to Q. alba, American White oak.  In many respects the Oregon oak is more similar to European oak species.  Thus, radial rays are more variable in size than American White oak and tend to show considerable discontinuity.  The annual rings are also diffuse sometimes with little obvious sign of the transition from one ring to another; in this respect Oregon oak is very unusual and the effect is worse (from the point of producing a well coopered barrel) than French oak.  The straightness of the grain was reasonably good but less so than American white oak.

 

The tyloses structure of the wood was also reminiscent of European oak being less well formed and thinner than American white.

 

This type of wood, if being used in cooperage would require, in the main, to be cleaved rather than quartersawn if leakage problems were to be avoided.

 

Conclusions

 

The analysis of Q. garryana is certainly very interesting.  As a native of the USA it has many of the characteristic of European oak, but, as a result of these characteristics it may prove difficult to produce good, tight cooperage.  Some aspects of the chemistry are also similar to European oak notably low levels of scopoletin but, on the other hand, the levels of hemicellulose breakdown products suggest it is more thermally stable than European oak.

 

It is strongly recommended that if barrel construction with Q. garryana is to be considered the wood should be well seasoned and its chemistry should be examined for suitability before barrel construction begins.  The wood should also be handled in the manner used for European oak rather than American oak i.e. the wood should be cleaved, attention to the straightness of the grain should be watched carefully and the stave thickness should be greater.

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