Soap-Making Manual / A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant.

by Edgar George Thomssen

METHOD FOR FURTHER IMPROVEMENT OF COLOR.

A further improvement of the color of the tallow may be obtained by freeing it from a portion of its free fatty acids, either with or without previous Fuller's earth bleaching.

To carry out this process the melted fat is allowed to settle and as much water as possible taken off. The temperature is then raised to 160° F. with dry steam and enough saturated solution of soda ash added to remove 0.5 per cent. of the free fatty acids, while agitating the mass thoroughly mechanically or by air. The agitation is continued ten minutes, the whole allowed to settle for two hours and the foots drawn off. The soap thus formed entangles a large proportion of the impurities of the fat.