Official Journal of the Japan Wood Research Society
Table 1 Colour parameters of Q. robur and Q. petraea heartwood extracts. Incidence of different solvents or mixtures of solvents
From: Origin and characterisation of the extractable colour of oak heartwood used for ageing spirits
Q. robur | Q. petraea | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Aa420 | L*b | a*b | b*b | C*b | h*b | Aa420 | L*b | a*b | b*b | C*b | h*b | |
Water | 3.6 | 46.6 | 6.3 | 21.1 | 22.0 | 1.3 | 3.5 | 49.5 | 5.4 | 19.2 | 19.9 | 1.3 |
Ethanol–water (5/5) | 4.1 | 42.0 | 7.1 | 23.5 | 24.5 | 1.3 | 3.9 | 46.7 | 6.8 | 22.6 | 23.6 | 1.3 |
Ethanol–water (9/1) | 4.7 | 37.6 | 10.1 | 24.9 | 26.8 | 1.2 | 4.9 | 32.4 | 10.4 | 26.5 | 28.4 | 1.2 |
Methanol–water (9/1) | 4.6 | 38.2 | 9.8 | 25.2 | 27.0 | 1.2 | 4.5 | 31.8 | 10.1 | 24.3 | 26.3 | 1.2 |
Acetone–water (7/3) | 5.7 | 27.3 | 5.2 | 11.5 | 12.6 | 1.1 | 5.6 | 25.8 | 6.2 | 13.2 | 14.6 | 1.1 |
Diethyl ether | 2.2 | 61.4 | 3.4 | 29.4 | 29.6 | 1.4 | 2.6 | 58.7 | 2.6 | 28.7 | 28.8 | 1.5 |