Around the end of the 19th century, olive production in Lesvos was estimated at 25,000 tons, exports at 10,000 tons of olive oil and 3,800 tons of soap, with the number of olive trees being around 10 million, of which 2 million at the town of Plomari. In comparison, in the mid-16th century the island was producing just 236 tons of olive oil and 1,026 tons of olives, with the number of olive trees in the mid-17th century at the town of Plomari being just 17,774, corresponding to roughly 45 trees per owner.

Such growth rates were the result of the mechanization of the productive process during the last quarter of the 19th century, which constituted the starting point of the technological change and modernization that reached its peak in the 20th century. However, one can observe that, for many decades, these modern forms of production coexisted with the archaic forms of the manual cylindrical grinder and the animal-powered press of the Hellenistic period.

The mechanization period (1870-1890) did not alter the stages nor the method of the production process; rather, it kickstarted a new age by redefining the “rhythm” of production and, thus, the production quantitative outcome—especially a new reality in regard to facilities, funds, and production costs. This production framework would remain unaltered, and with minimal changes in respect to energy supply (import of diesel engines, electricity), until the end of the 1930s, when centrifugal industrial separators were integrated, thus completing the configuration of the model of the production process‘ first mechanization, which would be maintained until the end of the 1950s.

The rapid growth of Lesvos’ exports after the mid-19th century due to an increased demand for olive oil and its products, as well as the island’s transitory role—which acted as a warehouse of goods destined for the coasts of Asia Minor—contributed decisively to the development of the olive oil and soap industry. The years between 1875 and 1895 are deemed Lesvos’ golden age of soap production and trade. In 1909 at the town of Plomari alone, for example, one could find 12 soap factories, 10 olive oil mills, 1 hydraulic flour mill, 2 kernel olive oil factories, and 2 steam-powered olive oil mills.

The new economic and political conditions of the early 20th century, the instability due to the Balkan Wars and World War I—and especially the 1922 Asia Minor disaster—led to the complete cut off of traders from Asia Minor and the Black Sea. This led to a gradual deindustrialization, evident, e.g., at the town of Plomari during the 1960s, when only 3 soap factories were operative, which, along with the olive oil mill facilities, were eventually abandoned.