The Subsequent Alterations
As Abbot Couture mentions, at the end of the 18th century AC, most of the manufactures preferred the quantity to the quality. Indeed the productivity was not big unless the press had big weights and they tried all the time to increase it as much as possible.
Therefore, they left the olives for a few days to strain or they boiled them before the crushing. It is worth mentioning that Katon and Koloumella expressed their concern about the quantity of olives and oil. In addition, they suggested collecting the olives cautiously without hitting by canes, all the machines to be cleaned before and after their use and to crush the olives right after their collection.
We meet the same advice in the 17th and the 18th century at some agriculturist's works, which aimed to the improvement of the oil quality and to the exploitation of olive cake. At that time the olive plantations and the olive mills expanded throughout Corfu (Sordinas, 1971), the press with screw appeared in Italy and in France where efforts were made to increase the productivity by the hanging the press from domes.
Moreover, the agriculturists talk about some "technological barriers". Therefore Bernard underlines the aloofness of the aristocrats, who as the owners had the authority to keep the olive cake, they do not care about the improvement of the compression. In every area, there was something to be proposed, like the winch to improve the system.
Although some of these efforts were not accomplishable (Bella, 1784), they are characteristic of the wish for the improvement of olive mills. In some cases, the hydraulic power was used for the crushing. (Amouretti, Comet, 1989).
At the beginning of 19th century all the systems for crushing which were familiar from Ancient Times, coexisted: the spin, the smash in mortars, the presses with crowbar and weights and the presses with screw bar one-column or two-column. Although the presses with wheel or with the combination of winch and weights had stopped being used for the oil production, the other kinds of presses kept on functioning.
Therefore, we meet them simultaneously at the same area or at the same environment. Either wooden or stone, their continuous function is not a result of the modesty of agricultural societies. Each one had its benefits and its drawbacks. For that reason, the adoption of a new function although the previous one was effective needed consideration.
Among the alterations which were accomplished at the end of the 19th century and at the beginning of the 20th century it is worth mentioning that the increase of oil production in some countries like Greece and Tunisia, while in traditional oil producing countries like Spain, Italy and France, the olive cultivation occupies the mountainsides as well. At the same time, the competition of seed oils begins.
With the introduction of the mechanically operated mill, the press with screw bar obtained the priority, while even if it was smaller it was more resilient. Furthermore, with the new system, the risk of breaking, chapping or mangling, which were the main problems of this kind of press, partly disappeared. However, the farmer could not manufacture it on his own. (Therefore, many presses with crowbar continue operating until the 20th century). Another factor, in the 19th century, was the drop at the manufacturing cost of small presses.
At any rate, we have to mention that despite all the alterations, no great technological conversion is accomplished. Only with the introduction of the modern centrifugal presses, these machines which were made in the Ancient Times, disappear after centuries of operation.