The Olive Harvest: When and How Olives Are Picked
More of an olive oil’s quality is decided in the fortnight around harvest than in the whole rest of the year. Pick early and you get green, bitter, long-lived oil in small quantity. Pick late and you get more of a gentler oil that will not last.
Ask a grower when the harvest starts and you will not get a date. You will get a judgement about a trade-off. The olive accumulates oil through autumn while its polyphenols — the bitter, peppery antioxidant compounds — peak early and then decline. Every week you wait, you gain litres and lose character and shelf life. Everything else about the harvest, from the machines to the crates, follows from where a grower chooses to sit on that curve.
Reading ripeness
The signal growers watch is veraison: the colour change as the fruit turns from green through straw and purple to black. A grove does not turn all at once, so the decision is made on the proportion of fruit that has begun to change. Oil for the greenest, most pungent, most polyphenol-rich styles is picked while most of the fruit is still green or barely turning. Mainstream extra virgin is generally picked around the point where a good part of the grove has gone purple. Wait until everything is black and soft and you will get the most oil per kilo, along with a flat, sweet product that oxidises quickly — and you will also have taken resources the tree needed to build next year’s crop, which deepens the biennial swing.
Table olives run to their own calendar entirely. Green table fruit is picked hard and unripe, before any colour change, for firmness and for its response to curing; black table olives are picked ripe. Both are picked far more carefully than oil fruit, because a bruise that is irrelevant in a mill is a defect in a jar.
| Method | How it works | Suits | Trade-off |
|---|---|---|---|
| Hand picking | Fruit stripped by hand into a bag or onto nets | Table olives, steep ground, old trees, top quality | Slowest and by far the most expensive; the gentlest on fruit and tree |
| Combs and rakes | Hand or battery-powered combs pull fruit onto nets below | Small groves and family harvests | Cheap and effective; still labour intensive |
| Trunk shakers | A tractor-mounted clamp vibrates the trunk; fruit falls into an inverted umbrella | Traditional large-canopy trees | Fast, but needs access and can damage bark if badly used |
| Straddle harvesters | A machine drives over hedgerow rows, beating fruit off continuously | High-density and super-high-density plantations | Extremely fast and cheap per litre; only works on purpose-planted hedges |
What happens between the tree and the mill
This is the part nobody photographs and the part that ruins the most oil. Picked olives are living fruit. Piled deep in a sack they heat up, begin to ferment and start hydrolysing their own oil, which raises free acidity — the number that decides the grade. Fruit that sat three days in nylon sacks in a warm shed produces an oil with a musty, winey character that no mill can remove.
The fix is not expensive. Carry fruit in shallow ventilated crates rather than sacks, keep it out of the sun, and get it to the mill the same day. Within twenty-four hours is the working rule; the best producers work in hours. If you ever want to know whether a producer is serious, ask how long between picking and milling. The answer tells you more than any award.
At the mill the fruit is washed, crushed into a paste, and slowly stirred — malaxed — so the microscopic oil droplets coalesce. Temperature matters here: warmer paste releases more oil but drives off aromatics and degrades polyphenols, which is why cold extraction, conventionally under 27 degrees Celsius, costs yield and buys quality. The paste then goes to a centrifuge, which separates oil from water and solids. What comes out is simply fruit juice, and it is at its best that day.
Harvest choices you can taste
- Early harvest oils are green, bitter and peppery, high in polyphenols, and keep far better. You pay for them because there is less oil in the fruit.
- Late harvest oils are golden, sweet and mild, cheaper to produce, and go stale sooner.
- Bitterness and throat-catch are not faults. They are the taste of the antioxidants that also keep the oil alive.
- A harvest date on the label is the single most useful piece of information a producer can give you.
- Same-day milling matters more than the brand of equipment used.
- Table olives and oil olives are picked at different ripeness and handled with different care — a bruised olive is fine for oil and useless in a jar.
The olive harvest: common questions
When are olives harvested?
In the northern hemisphere, roughly October to January depending on latitude, altitude and the style of oil wanted. In the southern hemisphere the season falls around April to June.
Are green and black olives different varieties?
Usually not. They are the same fruit at different stages of ripeness — olives turn from green to purple to black as they mature.
Why do some producers pick early if it means less oil?
Because early-picked fruit gives greener, more bitter and peppery oil, far richer in polyphenols, which both tastes distinctive and lasts much longer. The lower yield is the price of that quality.
How quickly must olives be milled?
As fast as possible, and ideally within twenty-four hours. Fruit left in sacks heats and ferments, raising free acidity and creating musty defects that cannot be removed later.
Is machine harvesting worse than hand picking?
Not necessarily for oil. A well-run mechanical harvest that reaches the mill the same day beats a hand harvest that sits for three days. For table olives, hand picking still wins, because bruising shows.
What does cold extraction actually mean?
That the paste was kept below a defined temperature, conventionally 27 degrees Celsius, during malaxing. Warmer paste releases more oil but loses aroma and antioxidants.
If you only ever ask a producer one question, make it this : how many hours between the tree and the mill ? Everything else — the variety, the machines, the medals — is downstream of that number. I have tasted magnificent oil from ordinary fruit milled within three hours, and thin, musty oil from a famous grove whose fruit sat over a weekend. Speed is not glamorous and it is not expensive, and it is the closest thing this trade has to a secret.
Drawn from standard olive harvesting and milling practice across Mediterranean and southern hemisphere production.