Preparation of the Fat Corps

(a) Preparation of the Fat Corps. 

The success of enfleurage depends to a great extent upon the quality of the fat base employed. Utmost care must be exercised when preparing the corps. It must be practically odorless and of proper consistency. If the corps is too hard, the blossoms will not have sufficient contact with the fat, curtailing its power of absorption and resulting in a subnormal yield of flower oil. On the other hand, if too soft, the corps has a tendency to engulf the flowers so that the exhausted ones are difficult to remove and retain adhering fat, which entails considerable shrinkage and loss of corps. The consistency of the corps must, therefore, be such that it offers a semihard surface from which the exhausted flowers can easily be removed. Since the whole process qf enfleurage is carried out in cool cellars, every manufacturer must prepare his corps according to the temperature prevailing in his cellars during the months of the flower harvest.

Many years of experience have proved that a mixture of one part of highly purified tallow and two parts of lard are eminently suitable for enfleurage. This mixture assures a suitable consistency of the corps in conjunction with high power of absorption. The author carried out a series of experiments with various mixtures of vegetable fats, especially hardened vegetable fats which do not easily turn rancid. He also experimented with all kinds of antioxidants and glycoside splitting compounds, incorporating them into the corps before enfleurage. The result was a variety of interesting qualities and widely different yields of flower oils, but the highest quality of floral oils most true to nature resulted from the old-fashioned mixture of lard and tallow.

Mineral oils, too, have been suggested as bases for enfleurage work, and on a limited scale have been practically employed; but they offer no real advantage because their power of absorption is very small as compared with that of animal fats. Furthermore, it is exceedingly difficult to extract and isolate small quantities of absorbed flower oils from the mineral oils with alcohol or by other means.

Many other substances have been suggested as bases for enfleurage, and have been patented for this purpose, but none so far has attained any wide commercial application. For instance, according to French Patent 836,172, January 12, 1939 (I. G. Farbenindustrie A.-G.),²⁹ essential oils and natural flower oils are extracted by treatment of the plant material with esters of polyhydric aliphatic alcohols, containing at the most 6 carbon atoms, with fatty acids of high molecular weight, as obtained by oxidation of paraffin hydrocarbons of high molecular weight. Thus esters of glycol, glycerol, erythritol, mannitol, hexitol or trimethylolpropane may be used.

The fat corps is prepared in the Grasse factories during the winter months when they are not busy with the processing of flower crops. The crude pieces of tallow and lard, mostly of French and Italian origin, are purified according to a tedious old-fashioned method. The crude fats are carefully cleaned by hand, all adhering particles of skin and blood vessels removed, then crushed mechanically and finally beaten in a current of cold water. After all impurities have been removed, the fat is melted gently on a steam bath. Small quantities of benzoin (0.6 per cent) and alum (0.15 to 0.30 per cent) are then added. This preservation is very important, as otherwise the corps will turn rancid during the hot summer months. While benzoin acts as a preservative, the adding of alum causes impurities to coagulate during the heating ; when rising to the surface they can be skimmed off with a spoon. The warm fat is filtered through cloth, then left to cool and stand, so that any water may separate.

(During the past years chemistry has made great progress in regard to antioxidants for fats and oil, several of which could undoubtedly be used for preservation of the enfleurage corps employed in the Grasse region.)

The fat corps thus prepared is white, of smooth, absolutely uniform consistency, free of water and practically odorless. If well prepared and properly stored, it will resist rancidity for several years.

Some manufacturers also add small quantities of orange flower or rose water when preparing the corps. This seems to be done for the sake of convention. Such additions somewhat shade the odor of the finished product by imparting a slight orange blossom or rose note.