Cold Pressing: Why It Guarantees Superior Quality Olive Oil

Introduction

You've seen it mentioned hundreds of times on labels: "first cold press." It appears on gourmet food bottles, on supermarket oils, sometimes even on entry-level products sold for less than ten euros per liter. This omnipresent phrase has become an almost automatic marketing argument—to the point where we no longer really know what it means.

Yet, behind these four words lies a precise technical reality, with direct consequences on what you put on your plate. Understanding cold pressing means understanding why two "extra virgin" olive oils can sometimes have nothing in common. It's also the tool that will prevent you from being fooled on your next purchase.

What is cold pressing? Technical definition

Cold pressing refers to a mechanical extraction process for olive oil in which the temperature of the olives and the paste never exceeds 27 °C at any point in the process. This threshold is not arbitrary: it is set by European Regulation EC No 1019/2002, which governs the terms that can be used on olive oil labels.

To understand what this practically entails, here's how the extraction unfolds:

1. Crushing. The olives—fruits and pits—are mechanically crushed into a homogeneous paste. This step naturally generates heat through friction. In cold extraction, the temperature is continuously monitored and controlled.

2. Malaxation. The paste is slowly stirred for 20 to 45 minutes. This malaxation allows the oil micro-droplets to group together into larger droplets, facilitating separation. This is where temperature control is most critical: the longer or higher the temperature of malaxation, the higher the yield—but the more the quality risks being compromised.

3. Extraction. The oil is then separated from the paste and vegetable water, either by centrifugation (the dominant modern method) or by mechanical pressing (an older method, now marginal). The centrifuge, or decanter, separates the liquid and solid phases using centrifugal force.

4. Filtration (optional). The oil can be filtered to remove suspended impurities, or sold cloudy (unfiltered). Both approaches have their proponents.

The entire process—from crushing to bottling—falls under what is called olive oil production and manufacturing.

Why 27 °C maximum? The science behind the standard

The 27 °C figure didn't come out of nowhere. It corresponds to the threshold below which the most fragile compounds of the olive are fully preserved.

Polyphenols, first affected by heat. Polyphenols are natural antioxidants present in olives, partly responsible for the bitter taste and characteristic pungency of quality oils. These molecules are thermolabile: beyond 27–30 °C, their degradation accelerates. At 40 °C, a significant fraction is destroyed. At 50 °C and above, losses become massive.

Volatile aromas, which literally evaporate. The aromatic compounds responsible for the fruity, herbaceous, and floral notes of olive oil are, as their name suggests, volatile. Heat causes them to evaporate even before the oil is bottled. An oil extracted at high temperatures will have an impoverished, sometimes neutral, aromatic profile.

Fatty acids, prematurely oxidized. Olive oil is rich in oleic acid (omega-9) and contains polyunsaturated fatty acids (omega-6, omega-3). The latter are sensitive to oxidation, a process accelerated by heat. Hot extraction produces an oil whose peroxide value—an indicator of initial oxidation—is immediately higher, which shortens its shelf life.

In summary: each additional degree beyond the regulatory threshold represents a compromise between yield and quality. Producers who choose cold extraction make the opposite choice: less oil extracted, but an oil that preserves the integrity of what nature put in the olive.

Cold pressing vs hot extraction: the comparison

Here's a direct comparison of the two extraction methods, based on the criteria that truly matter.

The economic logic is clear: by heating the olive paste, more oil is extracted from the same fruits. For an industrial producer, this is an attractive equation. For a producer focused on quality, it's a path not taken.

The nutritional benefits of cold extraction

Cold-extracted oil is not only better tasting. The nutritional differences are measurable and documented.

Polyphenols, leading the way. Several comparative studies show that cold-extracted oils can contain two to three times more polyphenols than oils extracted at higher temperatures. These antioxidants—oleuropein, hydroxytyrosol, tyrosol—are associated with cardiovascular protective and anti-inflammatory effects. The European Food Safety Authority (EFSA) has also validated a health claim for olive oil polyphenols, provided the oil contains a minimum of 5 mg per 20 g. This threshold is largely exceeded in quality cold-extracted oils—and often difficult to achieve in hot-extracted oils.

Vitamin E. Olive oil is one of the most interesting dietary sources of tocopherols (vitamin E). This vitamin is fat-soluble, which theoretically makes it heat-stable—but it also acts as an antioxidant in the oil itself, and a part is "consumed" to protect other compounds during hot extraction.

Fatty acids, intact. Oleic acid, which is predominant in olive oil, is relatively heat-stable. However, the small proportions of polyunsaturated fatty acids (linoleic, alpha-linolenic) are more fragile. Cold extraction preserves them in their original molecular configuration.

These nutritional benefits are directly linked to the health benefits of olive oil. To fully benefit from them, the oil must have been properly extracted from the outset.

The taste advantages: what you perceive in the glass

A comparative tasting between a cold-extracted oil and a hot-extracted oil is often revealing, even for a non-expert palate.

Bitterness and pungency. These two sensations—bitterness in the mouth and a slight burning in the back of the throat—are the signatures of polyphenols. An oil rich in polyphenols will be distinctly bitter and pungent. This is not a defect: it is proof of quality. Hot-extracted oils, depleted of polyphenols, are milder, more "easy"—but also emptier.

Aromatic complexity. A cold-extracted oil from olives harvested at optimal ripeness develops a bouquet that can evoke fresh grass, raw artichoke, green tomato, almond, or herbs de Provence depending on the variety. These nuances are the result of an extraction that respects aromatic compounds. When hot, this bouquet fades in favor of a more neutral taste, often described as "greasy."

Persistence. The length on the palate of a good cold-extracted olive oil is significantly superior. The taste develops in successive waves—fruity, bitter, peppery—before gradually fading. An oil of lesser quality, whether hot-extracted or simply made with insufficient quality olives, quickly disappears from the palate without leaving a trace.

"First cold press": an obsolete term, let's be honest

Let's be clear: the term "first cold press" is technically outdated, and the vast majority of producers who use it do so out of habit or for marketing, without it corresponding to a precise mechanical reality.

Where does this term come from? Historically, mills used hydraulic presses or stone mills. The principle was simple: the olive paste was pressed once (hence "first press"), yielding the finest oil. Then it was pressed a second time, sometimes hot, to extract the rest. "First cold press" therefore referred to the initial, best extraction.

What it means today. Since the 1990s, continuous centrifugation has replaced presses in almost all modern mills, including artisanal ones. The centrifuge performs only one extraction—so there is no longer a "first" or "second" press in the literal sense. Referring to "first press" for an oil extracted by centrifugation is technically inaccurate.

What the regulation says. The European regulation has decided: the authorized term for oils extracted by centrifugation is simply "cold extraction" (or "cold pressed"). The mention "first cold press" remains tolerated for oils actually produced by mechanical presses—a method now rare.

To delve deeper into first cold press and its subtleties, you'll find a detailed analysis in our resources.

How to verify that an oil is truly cold-extracted

The mention on the label is not enough. Here are the concrete elements to check before buying.

1. The legal mention is a necessary condition, not sufficient. The label must state "cold extraction" or "cold pressed". Without this mention, the matter is settled. With this mention, verification continues.

2. Price is a brutal filter. It is economically impossible to produce a quality extra virgin olive oil—cold-extracted, from olives harvested at optimal ripeness, with a lower yield—and sell it below 15 to 20 euros per liter. Below this threshold, something does not correspond to what is displayed on the label: either the quality of the olives, or the extraction method, or compliance with the extra virgin specifications. Often all three at once.

3. Labels and certifications. PDO (Protected Designation of Origin) imposes strict specifications that, in most cases, include cold extraction. Organic labels (AB) do not in themselves guarantee taste quality, but often come with more rigorous production practices.

4. Traceability and producer transparency. A serious producer can tell you: the olive variety, the harvest date, the time between harvest and mill (ideally less than 48 hours), the maximum temperature reached during extraction. If this information is not found, ask for it. The absence of a response is a response.

5. Tasting. Persistent pungency and bitterness are the most reliable indicators of an oil rich in polyphenols—hence a careful extraction. A mild, neutral oil without character is very likely to have been extracted under unfavorable conditions, regardless of the label's mention.

6. Visiting the producer. Nothing replaces a visit to the mill. Observing the process, questioning the producer, tasting the oil directly at the mill: this is the most direct way to recognize the quality of an olive oil.

Cold pressing at Moulin de Bournissac, partner of Mas des Thorades

At Mas des Thorades, cold extraction is not an option: it is the prerequisite for everything else. Here's how this translates concretely into our process.

From tree to mill in less than 24 hours. Olives harvested in the morning are brought to the mill in the afternoon of the same day. This delay is non-negotiable: every hour spent in a pile increases the fermentation of the paste and the acidity of the oil. Quality is achieved even before crushing begins.

Continuously monitored temperature. We equip our equipment with temperature probes and monitor readings throughout the extraction. The 27 °C threshold is not a limit to approach: it is a limit never to be reached. In practice, we generally operate between 18 and 22 °C.

Short malaxation, maximum quality. We limit malaxation time to 25–35 minutes depending on the batches. Prolonged malaxation increases yield but degrades polyphenols and exposes the paste to oxidation. The choice is made even before starting.

Total traceability. Each bottle is traceable back to the plot and harvest batch. Extraction temperature data is retained. We do not sell oil based on a label mention: we can document every step.