From plant to bottle: how extra virgin olive oil is produced | Olio Limera
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From plant to bottle: how extra virgin olive oil is produced
Understanding how an extra virgin olive oil is made helps in making better choices. In this practical guide, we will clearly examine all the phases: harvesting, crushing, malaxation, cold extraction, filtration, and storage. This is where the sensory profile, polyphenol content, and final quality are determined.
The oil cycle: the phases that truly matter
- Harvesting (controlled ripening, healthy olives)
- Transport (ventilated crates, short times)
- Defoliation and washing
- Crushing (pulp breakage)
- Malaxation (coalescence of oil droplets)
- Cold extraction (oil/water/solid separation)
- Filtration (stability, clarity)
- Storage (stainless steel, nitrogen, darkness)
- Bottling (dark bottles, anti-refill caps)
Harvesting: timing and methods that make a difference
The harvesting window ranges from true veraison to the desired ripeness. Olives that are too green: low yield but high polyphenols; too ripe: high yield but a flat aromatic profile. Two approaches:
- Manual/selective: slower, ideal for top quality and delicate cultivars.
- Assisted/mechanical: shakers and nets; high quality if done quickly.
Practical rule: process the olives within 12–24 hours of harvesting. Avoid closed sacks: they encourage fermentation and defects (heated, vinegary).
Crushing and malaxation: where aroma is built
Crushing breaks the drupe. The type of crusher (hammers, discs) influences bitterness/pungency and the green profile. During malaxation, the paste is stirred for 15–40 minutes: this is where the micro-droplets come together.
| Phase | Key Parameter | Recommended Range | Impact on Quality |
|---|---|---|---|
| Malaxation | Time | 15–30 min | More aroma, watch out for oxidation |
| Malaxation | Temperature | 24–27°C | Preserves volatile compounds and polyphenols |
| Extraction | Paste temperature | ≤ 27°C | “Cold-pressed” as per standard |
Extraction: what "cold pressing" really means
Cold extraction indicates that the oil is obtained with processing temperatures ≤ 27°C. For the consumer, this means: better preservation of green aromas, higher polyphenol content, lower oxidation. Modern decanter systems (two or three phases) separate oil, water, and pomace: process cleanliness, stable yields, fewer defects.
Filtration: why to do it (immediately)
Filtration removes micro-particles and vegetation water that accelerate hydrolysis and rancidity. An unfiltered oil can be pleasant initially but is less stable. Early filtration (using cartridges or membranes) improves shelf-life and clarity.
Storage and preservation: quality must be protected
- Stainless steel tanks at controlled temperature (14–18°C)
- Inert gas with nitrogen to reduce oxygen contact
- Dark and cool: light and heat degrade aromas and vitamin E
- Bottling in dark glass or tin, anti-oxygen caps
Pro tip for home: always close the bottle, avoid near heat sources, consume within 4–6 weeks of opening.
The acidity of oil: how to read it (and why you don't taste it)
Free acidity (expressed as oleic acid) measures the degradation of triglycerides. To be extra virgin, it must be ≤ 0.8%. You don't "taste" it: it's read on the label or technical sheet. Very low values often indicate healthy olives and a rapid, careful process.
How to choose a true extra virgin olive oil
- Clear origin and harvest indicated (campaign or month)
- Cold pressed and filtered declared
- Sensory notes: balanced fruitiness, bitterness, and pungency
- Storage: dark bottle, clearly visible batch and best-before date
The Limera method in 5 points
- Harvesting at the right degree of ripeness and rapid processing
- Temperature control during crushing/malaxation (≤ 27°C)
- Latest generation decanter extraction
- Early filtration for stability and clarity
- Storage in stainless steel, nitrogen, and bottling in dark glass
