160 Jmirnnl of Agriculture, Victoria. flO March, 1917. 



Olives are sent to Dookie College from a number of different districts 

 for oil extraction, and it is noticeable tliat the percentage of oil per 

 cwt.. of fruit varies considerably, also the flavour, even in the same 

 variety grown in a different environment. Thus it may be inferred 

 that each locality needs its special variety, and it would probably be an 

 advantage if small plantations of different varieties were now formed 

 throughout the State for future reference, when the growth of the olive 

 will likely become more general. The trees, established in the dry areas 

 of the State, would on account of their drought resistance and longevity, 

 prov© not only beneficial for shade purposes, but would also give some 

 return. 



The process of extracting the oil is a comparatively simple one. The 

 olives are picked, and bruised as little as possible when handling. All 

 leaves should be picked or winnowed out, and any dirt removed. The 

 fruit is then spread on a floor to a thickness of 3 inches for some days. 

 If the quantity of olives is larger than can be crushed and pressed 

 before moulds appear, it should be sprinkled with salt and turned 

 occasionally, otherwise the oil is apt to have a mouldy flavour. Though 

 olives crushed just as they are picked give a finer oil, the process of 

 extraction is much more difficult, as the slimy mucilaginous matter 

 which runs out with the oil and juice prevents some of the oil from 

 rising. By keeping the olives for several days on a floor, physiological 

 changes take place within the olives which frees the oil from the 

 mucilaginous pulp. 



The first process in the oil extraction is to pass the olives through a 

 machine that thoroughly macerates the flesh, but does not crush the 

 stones. The pulp is then put in coir matting bags .shaped like huge 

 tam-o'shanters, or wrapped in esparte or other strong fabric. The bags 

 are then put in the cage of the press, a steel plate and a wire mat being 

 placed between each bag. The wires of the mat are about the thickness 

 of No. 8 fencing wire. The part played by these wire mats is to facilitate 

 the flow of the oil from the centre of the bags along the grooves formed 

 where the wires touch the steel plates. If these mats are not used, owing 

 to the pulp on the edges of the bags becoming so compressed, some of 

 the oil from the centre does not get through, and so remains in the 

 central mass of pulp. The oil from this first pressing is the finest virgin 

 oil. 



In the process of pressing the oil issues with the dark watery extract 

 from the pulp, and is caught in a vessel at the mouth of the floor of the 

 press. This is poured into a tinned vessel which has a tap a foot or 

 15 inches from the top, and a tap at the bottom to allow some of the 

 liquid to ruu out when the tin is full. In order not to disturb the oil, 

 which floats on the watery matter, the liquid from the press is poured 

 into a funnel attached to a tube that opens at the bottom of the tinned 

 vessel. When the oil has remained for a time in the tin the upper tap 

 is turned and the oil flows into a similar vessel as the first, then washed 

 in clean water. The oil is now passed through a filter of cotton batting, 

 and afterwards forced through a thick wad of cotton batting in a 

 specially-made filter, and allowed to remain for a time for any moisture 

 or other matter present to settle. Small lots of oil are usually filtered 

 through ordinary filter paper, when the oil comes out bright and clear, and 

 ready for bottling. The oil should be exposed to the air or light as little as 



