<\/span><\/h2>\n\n\n\nAfter optional defoliation and washing, the olives undergo milling (or crushing)\u2014the heart of the extraction process. This first stage consists of breaking the olives to rupture the cell walls and release the juice (oil and vegetation water). The result is a semi-fluid olive paste, made of a solid part (fragments of peel, pulp, and pits) and an emulsified liquid part (oil mixed with water). From this paste, through subsequent stages, the oil is separated.<\/p>\n\n\n\n
A proper milling process must break all the oil-bearing cells to maximize yield, without overheating or oxidizing the paste. This ensures that aromas and heat-sensitive nutrients remain intact. Hence the term cold extraction<\/em>, meaning that processing temperature remains below 27\u00b0C.<\/p>\n\n\n\n<\/span>Olive extraction methods: tradition and modernity<\/span><\/h2>\n\n\n\nOver time, olive oil technology has developed various milling and extraction methods. Broadly, there are two main systems: traditional (press-based) and modern continuous (centrifugal). Both aim to separate the oil from the solid parts, but with different techniques and results.<\/p>\n\n\n\n
<\/span>Traditional milling<\/span><\/h2>\n\n\n\nTraditional milling used two main tools: the press with mats (fiscoli<\/em>) and the stone mill (molazza<\/em>). After malaxation, the olive paste was spread on stacked filter mats and pressed to extract the oil must, separating it from the pomace.<\/p>\n\n\n\nThough this system could yield fine oils, it was slow, labor-intensive, and unhygienic\u2014the natural fiber mats retained residues that caused fermentation and oxidation defects known as \u201cmat flavor.\u201d Today, presses still in use employ synthetic discs instead.
The stone mill, with large granite wheels that slowly crush the olives, is gentler than modern crushers, producing less heat and emulsion, and yielding harmonious oils with slightly fewer polyphenols. However, the slower process exposes the paste to oxygen, leading to oxidation and shorter shelf life.<\/p>\n\n\n\n
Traditional milling can yield high-quality oils with balanced profiles but is rarely used today due to low efficiency and high maintenance costs.<\/p>\n\n\n\n