1. Without the aid of heat: absorption or enfleurage a froid.
The absorption method, known as enfleurage, applied to those flowers which continue to produce volatile oil even after they have been removed form the stem (p. 246), depends on the capacity of fats or fatty oils to absorb the oil volatilized by the flowers and to hold it. This process is carried out in a relatively primitive manner. As already stated on p. 246, it is applied to jasmine, tuberose, jonquil, lily of the valley, and mignonette.
For the purpose of enfleurage, so called chassis are used. These are wooden frames 5 cm high and 50 to 80 cm square. A glass plate is supported in the middle of the frame. On either side of this glass plate a layer of fat about 3 mm in thickness is spread in such a manner as to leave a margin 4 cm wide (fig. 61, p. 259). The flowers, deprived of their calices, are then spread over this layer of fat (enfleurer) (fig. 62, p. 261). In order to enlarge the surface of the fat exposed to the flowers criss cross furrows are drawn through it with the aid of a spatula. Thirty-five to forty of the chassis thus prepared are piled one on top of the other to the height of a man. As a result the flowers are enclosed in small chambers, as it were, between two layers of fat, which absorbs the aroma. The length of exposure depends on the kind of flower: jasmin 24 hours, jonquil 48 hours, tuberose 12 hours. Moreover, the last mentioned are placed on fat in the unopened stage and are allowed to expand while resting on the fat. If they are placed on the chassis fully developed they are spoiled by the next day (pourri). After the flowers have remained on the fat for the requisite length of time, they are removed by a rap on the frame or with the aid of the fingers (defleurer) (fig. 62, p. 261). The chassis are then charged anew but this time on the other side so that the flowers now rest on the layer of fat which in the previous exposure was the upper one, thus producing a more even charging of the fat with perfume. This process can be repeated as often as desired until the fat has absorbed a sufficient amount of oil. The price of the pomade (Pommade francaise) depends on the number of exposures. As a rule the fat is exposed 30 times.
Fig. 61.Spreading the layer of fat on chassis (Patage des chassis). Parfumeries de Seillans, Dep. du Var, Southern France.
The production of a good pomade depends first of all on the character of the fat which must be purified with great care. In as much as lard is too soft and beef fat too hard, a mixture of both is commonly used for enfleurage, e. g. 40 parts of beef fat and 60 parts of lard. During the hottest months a mixture of equal parts of both is used. The fat of recently killed animals is cut into pieces and all impure or malodorus parts are removed. The good parts are then further reduced and rendered in a special apparatus, the tissues and other impurities being removed. In order to remove traces of blood, the mass thus resulting is ground between mill stones with the aid of water until the latter remains clear. The fat is next melted at the lowest possible temperature in a jacketed steam pan and alum is added. The alum facilitates the coagulation of impurities which rise to the surface and can be removed with the aid of a skimming spoon. The molten mass is allowed to stand for several days, the separated water is removed and the fat strained through linen. The fat thus obtained is preserved in one of several ways. The fat is digested for an hour with gum benzoes (about 1 to 3 g for each kilo of fat)1) and either orange flowers (according to Pillet 250 g for each kilo of fat)2) or, less frequently, with rose water (about 40 g for each kilo of fat). This mixture is then allowed to stand for several hours and the fat, freed from water drawn, into the containers. This is done in May at the time of the orange flower harvest. The fat thus prepared (le corps prepare) is said to be very stable. Occasionally a simpler method is employed. The purified fat is digested with gum benzoes (axonge benzoinee) or with tolu balsam (axonge toluinee) or for a few moments only with poplar buds (axonge populinee).
1) Comp. S. Piesse, Chimie des Parfums. Paris 1897. pp. 59, 60; J.-P. Dur-velle, Fabrication des Essences et des Parfums. Paris 1908. p. 77. See also Jeancard et Satie, Pecherches analytiques sur quelques essences de jasmin [Bull. Soc. chim. III. 23 (1900), 555] and Hesse, Uber atherisches JasminblutenOl [Berl. Berichte 34 (1901), 291].
2) Report of Schimmel & Co. Oktober 1900, 37.
Fig. 62. Enfleurage (to the left) and defleurage (to the right). Against the walls the piles of chassis. Parfumeries de Seillans, Dep. du Var, Southern France.
The process here described is used almost universally. In a few instances only other "fat bodies" have been used, viz., olive oil or paraffin oil. These also must be of the very best quality, but do not have to be "prepared". Formerly behen oil (from Moringa pterygosperma, Gsertn.) was used extensively in southern France. It does not readily become rancid, but an excessive duty now prohibits its use.1)
Paraffin enjoys the advantage over fats because of its indefinite keeping qualities, but is little used for the reason mentioned below. When liquid oils are used, the glass plates of the chassis are replaced by wire screens, which serve as supports for woolen cloths saturated with the oil in question. The flowers are strewn on these cloths. The process is otherwise as described above. The perfumed oil, huile frangaise, huile par-fumee, huile antique, is finally expressed from the cloths by means of hydraulic presses. The pure oil is obtained from the pomade or from the huile francaise as from the concrete oils. The pomade is extracted with strong alcohol, either in flasks by continuous shaking or in factories with the aid of special stirring apparatus illustrated in fig. 64. The cylindrical vessels are supplied with mechanical stirring apparatus which cause the fat and alcohol to be intimately mixed. Here also the last traces of fat are removed by freezing. From the extraits aux fleurs thus prepared, the essences are obtained by removal of the alcohol.2)
The residual fat is no longer suited to enfleurage and, as corps epuise finds its way into the soap industry. The waste flowers are used either as fertilizer, or occasionally for the production of essences concretes.
According to Hesse3) the enfleurage with fat is preferable in every way to that with paraffin oil. Comparative experiments have revealed that paraffin has a much lower absorption capacity for odoriferous substances than fat, hence causing a much lower yield. Thus the enfleurage of 1000 kilo of jasmine flowers with fat yielded 1684 g of ethereal oil, whereas enfleurage with paraffin yielded but 1053 g oil.1)
1) Heckel, Rev. cultures coloniales 5 (1901), 258.
2) Jeancard and Satie, Abrege de la Chimie des Parfums. Paris 1904. p. 13.
3) Berl. Berichte 34 (1901), 293 ff.
Fig. 63. Enfleurage with the use of oil. On the chassis held in a diagonal position the cloath saturated with oil can be seen.
Parfumeries de Seillans, Dep. du Var, Southern France.