METHODS OK MANUFACTUKK. 11 



MANUFACTI HI: 01 OLIVE OIL. 



The processes of manufacturing oil I'mm th<> olive are very simple. 

 The following general description is taken from a report to the gov- 

 ernor of California by the State board of horticulture. The fruit U 

 picked when ripe and dried either in the sun or by means of dryers. 

 It is then crushed in a mill and the oil extracted by a powerful pi-ess, 

 the details of these processes varying in different mills. In some 

 places the olives are mixed with hot water before making even the 

 first pressing. The first oil coining from the press is called the " virgin 

 oil" and is the highest grade of salad oil. The pulp left from the 

 first operation is subjected to a much higher pressure to produce the 

 second-pressing oil. As a rule, this is mixed with the ''virgin oil." 

 The pulp is now treated w r ith hot water and pressed again, when a 

 third-grade oil is produced which is used for the table and also for 

 lubricating fine machinery and for burning. The pulp still contains 

 oily matter which is extracted with carbon disulphid, and used in 

 making castile soap and in dyeing. In this country very little of this 

 lower-grade product is made. The oil from the different pressings is 

 run into tanks with water and allowed to stand until the pulp and 

 gummy matters settle out. The oil is drawn off carefully, filtered, 

 and stored in a cool, dark place until ready to be bottled, as olive oil 

 becomes rancid very quickly if exposed to light and heat. 



The following letters from California manufacturers of olive oil 

 give in greater detail the processes used at the various mills: 



SANTA CLAKA, CAL., May 7, 1902. 



My olives are picked when the average is ripe, but not dead ripe. They are spread 

 on trays and allowed to evaporate a portion of the "water of vegetation" before 

 pressing. They are crushed in an old-fashioned crusher, a revolving granite wheel 

 worked by horsepower, and pressed in Italian oil sacks (bruscole), which are made 

 of a kind of rush (guinco marino), which I import for the purpose. Practically all 

 tin- work is done by "rule of thumb;" i. e., by careful study of the condition of the 

 < >livcs, etc. We try to keep the temperature of the pressing room at about 70 F., but 

 the olives are not heated and come in cold. The run of a pressure is a mixture of 

 water and oil, fine material of the olive, and oil. After the run has stood a short 

 time the oil has in part come to the surface and the water sunk to the bottom with 

 an intermediate stratum of a mixture of oil, water, and fine material. The oil is 

 skimmed off the surface as soon as it appears in sufficient quantity, and this skim- 

 ming is continued indefinitely until the oil is called for and filtered for bottling. The 

 processes are the old ones in use in all the old countries where oil is expressed, and, 

 so far as I can judge, the best known up to the present time. There is absolutely no 

 secret. All depends on an intimate knowledge of the olive and these processes, and 

 I employ selected Italians from the oil districts of Tuscany to secure efficient work. 

 Frequent experiments are tried here in various lines, hoping to lessen the labor, but 

 so far without any serious success. The De Laval Company tried a separator here 

 this winter, and we hope that the expert, now fully acquainted with the difficulties 

 to be met, may work out an oil separator or a series of separators which will take the 

 olive just picked and give the refined oil at the end of the process or processes. An 

 exceedingly able English mechanic has tried two experiments with a new press this 



