What Is an Olive Oil Mill
An olive oil mill is the facility where olives are turned into extra virgin olive oil. It is the heart of the production process: not a simple structure, but a complex system where every step — from receiving the olives to storing the oil — determines the quality of the final product.
In Italy there are two main types of mill:
- Own-harvest mill: processes its own olives, from groves it owns or manages directly. The oil produced is entirely controlled by the producer, from the tree to the bottle.
- Contract mill: processes olives from other farmers, who bring their own harvest and receive oil or a share of production in return. Common in olive-growing areas with high production density.
Frantoio Oleario F.lli Pace in Basilicata operates according to the first model: direct access to olive groves, manual harvesting, milling within 24 hours of harvest.
How the Milling Process Works
1. Receiving and Cleaning the Olives
The olives arrive at the mill immediately after harvesting. First, they are cleaned of leaves, twigs and debris using a leaf remover and washed with cold water. This step may seem trivial, but it's critical: any impurity can alter the organoleptic profile of the oil.
2. Crushing
The cleaned olives are crushed to break down the cellular structure and release the oil droplets present in the vacuoles. There are two main methods:
- Millstone crushing (traditional method): large granite wheels slowly rotate over the olives, crushing both the pulp and the pit. It takes longer, but some producers believe it better preserves certain aromatic profiles.
- Hammer or disc crushing (continuous method): faster, generates less heat, better preserves polyphenols. It is the prevailing system in modern high-quality mills.
3. Malaxation
The resulting olive paste is slowly worked in malaxers — vats with paddles that stir the paste to aggregate the oil droplets into larger drops, making the subsequent separation easier. Temperature and malaxation time are critical variables:
- Below 27°C, cold-extracted oil is produced, with a higher content of polyphenols, aromas and antioxidants.
- Higher temperatures increase oil yield but lower organoleptic quality.
4. Extraction by Centrifugation
The malaxed paste is transferred to a decanter — a horizontal centrifuge that separates the three components by density: oil (the lightest phase), vegetation water, and pomace (the solid part). The extracted oil is then passed through a vertical centrifuge to separate the last traces of water.
5. Storage
The oil is transferred to stainless steel containers, at a controlled temperature, protected from light. Proper storage in the months following production is decisive for preserving quality and shelf life.
Why Buy Oil Directly from the Mill
Buying oil directly from an olive oil mill isn't just a romantic choice. There are concrete reasons for it:
Complete traceability. You know exactly which groves the oil comes from, which cultivar was harvested, and when milling took place. With oil from large-scale retail, this information is almost always missing or vague.
Guaranteed freshness. Quality oil has a shelf life of 12–18 months if stored correctly. An oil you buy at the supermarket may already have 6–8 months of supply chain behind it before reaching the shelf.
Real value for money. High-quality mill oil costs more than industrial oil, but the comparison doesn't hold up: they are different products. A litre of artisanal EVO oil from a controlled mill compares to a DOC wine, not a supermarket table wine.
Support for the local economy. The historic olive groves of Basilicata, Puglia and Calabria exist because there are mills that give them economic value. Buying direct is an act that has a real impact on preserving these landscapes.
How to Recognise a Quality Mill Oil
Some practical indicators:
- Harvest date on the label (not just the expiry date)
- Declared cultivar: Ogliarola, Coratina, Leccino, Nocellara — each variety has a specific profile
- Certified cold extraction (below 27°C)
- Available chemical analyses: free acidity (< 0.8% for EVO), peroxide number, total polyphenols
- Dark bottle or opaque tin: quality oil is never sold in transparent containers
The Oil of Frantoio Oleario F.lli Pace
Produced at the gates of Pietragalla, in the heart of Basilicata, Olio Pace comes from groves cultivated using traditional methods and manual harvesting. Milling takes place within 24 hours of harvest to ensure maximum freshness, with cold extraction to preserve polyphenols and organoleptic profile.
You can buy it directly on our website — mill oil, with no middlemen.
