Olive pressing

From olives to oil, through a controlled process

Olive milling is the moment when the quality of the raw material meets the experience of the mill master and the precision of technology.

At Frantoio Paolocci in Vetralla, every phase is carefully monitored: from the delivery of the olives to the storage and bottling of the extra virgin olive oil.

The process takes place exclusively through mechanical procedures, without chemical reagents or additives. Processing times, temperatures, and conditions are controlled to respect the characteristics of the olives and obtain a clean oil, recognizable and consistent with the quality of the raw material.

The new Pieralisi Leopard 8 plant

Frantoio Paolocci has chosen to invest in a new Pieralisi Leopard 8, a centrifugal extractor based on DMF – Decanter Multi Phase multi-phase technology.

The plant allows for the extraction of oil without added water, keeping the different products obtained during processing separate:

  • oil;

  • pomace;

  • olive pulp, also called pâté.

Leopard technology combines the continuity of a modern centrifugal plant with the possibility of carrying out batch processing, which is essential to keep the olives from different producers separate and identifiable.

The new machine does not replace the expertise of the mill master; it makes it more precise. Each batch requires the control of times, temperatures, speeds, and conditions of the olive paste.

Batch processing and traceability

Olives delivered by different producers are managed through batch processing.

This means that each batch is identified and kept separate throughout the production process.

Upon arrival, the olives are:

  • checked;

  • defoliated;

  • weighed;

  • associated with the producer's data;

  • identified with batch number, date, time, and weight of the delivered batch.

This organization ensures traceability, transparency, and control throughout the milling process.

The milling process

1. Olive delivery and inspection

The process begins with the arrival of olives at the mill. The raw material is inspected to assess its condition and verify that the olives are intact and free from obvious alterations.

The quality of the oil depends first and foremost on the olives: no technology can completely correct a raw material that has been poorly harvested, stored, or transported.

For this reason, the initial inspection is an essential phase of the entire process.

2. Defoliation, weighing, and identification

Before processing, the olives are separated from leaves and plant material present after harvesting.

The batch is then weighed and identified using the producer's and delivery data.

The olives are placed in dedicated containers, keeping each individual batch separate until milling begins.

The leaves recovered during this phase are destined for compost production, entering the circular economy system of Frantoio Paolocci.

3. Washing

The olives are washed with air and water to remove dust, soil, small stones, and any remaining leaves.

Washing prepares a clean raw material for subsequent stages and contributes to maintaining correct hygienic conditions in the plant.

Water is used in this phase for cleaning the olives. When we talk about extraction without added water, we are referring instead to the subsequent phase of separating the oil from the paste.

4. Crushing

After washing, the olives undergo crushing.

In this phase, they are entirely ground, including pulp, skin, and pit, until a semi-liquid paste called olive paste is obtained.

Crushing breaks the fruit's cells and releases the small oil droplets contained within them. It is in this phase that the aromas that will characterize the oil's organoleptic profile are created.

5. Malaxation

The paste is transferred to the malaxers, tanks in which it is slowly mixed.

During malaxation, the small oil droplets released by crushing progressively combine, facilitating subsequent centrifugal separation.

This phase is controlled by fundamental parameters:

  • processing time;

  • temperature;

  • quantity of paste in the malaxers;

  • characteristics of the individual batch.

Malaxation is one of the most delicate moments of the entire process, as it can influence the aromatic profile and characteristics of the obtained oil.

6. Extraction with the Leopard 8

After malaxation, the olive paste is sent to the Pieralisi Leopard 8.

Inside the decanter, centrifugal force separates the different components of the paste based on their specific weight.

The multi-phase technology produces three distinct flows:

  • oil;

  • pomace;

  • olive pulp or pâté.

Extraction occurs without adding water to the paste, avoiding diluting the process with external water and reducing the production of vegetation water.

The water naturally present in the olives remains part of the processed material and is separated in subsequent phases.

7. Centrifugal separation

The oil freshly out of the decanter may contain small amounts of vegetation water and residual particles.

For this reason, it undergoes a subsequent centrifugal separation, which allows for the elimination of remaining particles and obtains a cleaner product.

This phase also occurs through physical and mechanical processes.

8. Control and filtration

The oil is filtered, eliminating humidity and microparticles that could compromise its stability during storage.

It is then checked and tasted to assess its sensory characteristics.

Filtration does not change the nature of the oil: it allows it to be better protected over time and to preserve its characteristics longer.

9. Storage under nitrogen

After filtration, the oil is stored in stainless steel tanks, placed in a temperature-controlled environment.

A storage system under a nitrogen or argon blanket limits the oil's contact with oxygen, helping to protect it from oxidative processes.

Light, heat, and oxygen are, in fact, among the main factors that can progressively alter the oil's characteristics.

10. Packaging at the mill

Finally, the oil is packaged directly at Frantoio Paolocci.

Bottles, tins, and bag-in-boxes are prepared at the Vetralla facility, maintaining control over the product until the package is sealed.

The lot, olive oil campaign, and minimum shelf life identify the origin batch of olives and ensure the full traceability of the packaged oil.

Cold extracted, without added water

The expression cold extracted indicates that the process is carried out at a temperature below 27°C. To achieve this, the mill has equipped itself with a refrigeration system: cold water is used in the various interspaces of the machines to ensure correct temperature control during the different phases.

The absence of added water, on the other hand, refers to the centrifugal extraction phase carried out by the Leopard 8.

These are two different but complementary characteristics:

  • temperature control characterizes the entire extraction process;

  • Leopard technology allows for separation without adding water to the extraction process.

This does not mean that water is never used in the mill: washing the olives and cleaning the plants remain indispensable operations. It means that water is not added to the paste to separate the oil.

Technology and the mill master's expertise

A modern plant does not operate on its own.

The final quality depends on the combination of:

  • olive conditions;

  • processing speed;

  • temperature control;

  • correct management of crushing and malaxation;

  • extractor adjustment;

  • plant cleanliness;

  • operator experience.

The Pieralisi Leopard 8 represents an advanced tool, but it is the expertise and experience of the company's mill masters that guide its operation.

This is our way of understanding the new tradition: using contemporary technologies without losing the knowledge built over time.

Frantoio Paolocci. A new tradition for olive oil.