MANUFACTURE OF OLIVE! OIL 4Q9 



easily shaken from the tree they are ripe enough. If they com- 

 mence to fall without vigorous shaking they are overripe. For 

 whatever purposes the olives are to be used they should be care- 

 fully gathered by hand, and imperfect, immature, or bruised fruit 

 rejected. Sound fruit is required for high-grade oil -or for hand- 

 some pickles with good keeping quality. 



THE MANUFACTURE OF OLIVE OIL 



Olive oil is made in this State with apparatus of both Cali- 

 fornian and European design, and, as a rule, there is made only 

 one, and at most but two, pressings of the pomace, which s then used 

 for fattening swine. In the frequent working over of the pomace, 

 and the close extraction of the oil, as practiced in Europe, we 

 have done little as yet. 



Olive oil is made on a small scale by a number of parties who 

 use home-made contrivances, or small, portable cider machinery 

 for the crushing and pressing. During the last few years quite a 

 number of mills have been erected at several points in California 

 and they have made a market for the olives produced by growers 

 who do not care to undertake manufacture. A detailed account 

 of oil making, including descriptions of buildings and machinery, 

 has been published by the University Experiment Station.* As 

 this is available to those who desire such specific information, 

 only an outline will be undertaken for the information of the gen- 

 eral reader. 



Drying. Extraction of oil from fresh olives gives the best 

 oil, but it is somewhat troublesome, and it is customary to partially 

 dry them. This partial drying is also useful to keep the fruit for 

 some time or for shipment before crushing. Place the olives in 

 layers not more than three inches deep, on trays that are stacked 

 in a dry, well-aired room, protected from the wind and the direct 

 rays of the sun. Turn daily until the fruit bec'omes well wrinkled. 

 This requires about eight or ten days, according to the degree of 

 temperature. The partially dried fruit may be stored in a dark 

 room where the temperature does not rise above sixty degrees 

 Fahrenheit, for three or four weeks without any serious deteri- 

 oration of oil. To hasten the drying process, artificial driers, con- 

 structed on the same principle as the fruit or hop driers, are 

 sometimes used. The olives are placed in a single layer upon 

 trays, and the drier is kept at a temperature of about one hundred 

 and twenty degrees Fahrenheit; at over one hundred and thirty 

 degrees Fahrenheit the quality of the oil may be impaired. The 

 drying takes about forty-eight hours more or less according to 

 the nature of the fruit. 



* "California Olive Oil: its Manufacture," by G. W. Shaw, Bulletin 159, Uni- 

 versity Experiment Station, Berkeley, Cal. 



