Vanilla is reduced to powder (PULVIS VANILLÆ; POUDRE DE VANILLE) by slicing it, and triturating the fragments with twice or thrice their weight of well-dried lump sugar. For SUCRE DE VANILLE, 11 parts of sugar are employed.
The following table given by Messrs Tieman and Harmann, in the Journal of the Berlin
Chemical Society, represents the quantities of Vanillin (the aromatic principle of Vanilla) contained in that substance, as obtained from different sources:—
| Vanillin per Cent. | |
| Mexican Vanilla (1873, harvest) | 1·69 |
| Mexican Vanilla (1874, harvest) | 1·86 |
| Mexican Vanilla Medium quality | 1·32 |
| Bourbon, best quality (1874-75) | 1·91 |
| Bourbon, (1874-75) | 1·97 |
| Bourbon, (1874-75) | 2·90 |
| Bourbon, Small medium (1874-75) | 1·55 |
| Java, best quality (1873) | 2·75 |
| Java, best quality (1874) | 1·56 |
VANILLIN. A crystallised substance obtained from pine juice by Messrs Tiemann and Harmann. It has been shown to be identical with the aromatic principle of Vanilla.
In a paper read before the Royal Society the authors have described the process by which vanillin was artificially prepared by them. They state that the sap of the cambium of coniferous trees contains a beautiful crystalline glucoside coniferine, which was discovered by Kartig, and examined some years ago by Rubel, who arrived at the formula C24H32O12 + 3 Aq. A minute study of this compound leads us to represent the molecule of coniferine by the expression, C16H22O3 × 2 Aq., the per centages of which nearly coincide with the theoretical values of Kubel’s formula.
Submitted to fermentation with emulsine, coniferine splits into sugar, and a splendid compound, crystallising in prisms, which fuse at 73°. This body is easily soluble in ether, less so in alcohol, almost insoluble in water; its composition is represented by the formula C10H12O3. The change is represented by the equation—
C16H22O8 + H2O = C6H12O6 + C10H12O3.
Under the influence of oxidising agents, the product of fermentation undergoes a remarkable metamorphosis. On boiling it with a mixture of potassium bichromate and sulphuric acid, there passes with the vapour of water in the first place ethylic aldehyd, and subsequently an acid compound soluble in water, from which it may be removed by ether. On evaporating the ethereal solution, crystals in stellar groups are left behind, which fuse at 81°. These crystals have the taste and odour of vanilla.
An accurate comparative examination has proved them to be identical with the crystalline substance which constitutes the aroma of vanilla, and which is often seen covering the surface of vanilla pods.