At a glance:
Olive oil doesn’t improve with age - freshness starts at harvest and gradually declines as oxygen, heat and light affect the oil over time. Harvest dates, flavour, aroma and storage all reveal more about an oil’s quality than a best-before date, while early harvest, high-polyphenol oils tend to start with more of the qualities that make fresh extra virgin olive oil special.
Why your olive oil may not be as fresh as you think
Most people think olive oil gets better with age. In reality, it’s the opposite.
Extra virgin olive oil is a fresh fruit juice, not a wine to be stored away and enjoyed years later. From the moment the olives are pressed, EVOO slowly begins to lose some of its flavour, aroma and natural compounds. Fresh olive oil should bring notes of grass, green tomato and a gentle peppery finish. An older, tired oil can taste flat, muted and lacking the character it had when it was first made.
If you’re not sure what to look for, our guide on how to taste olive oil explains the simple steps for identifying the flavours and aromas of a quality extra virgin olive oil.
The challenge is that many bottles give nothing away about when they were harvested or pressed. Without a harvest date - including the exact year not just mentioning a month- it can be difficult to know how fresh the oil really is - or how much of its original flavour and polyphenol content remains.
That’s exactly what we’re here to help with. In this guide, we’ll look at how to check your olive oil’s freshness, how long it really lasts, and what actually causes it to expire.
What does "fresh" olive oil actually mean?
Freshness in olive oil isn't a marketing term - it's measured from a specific date: the harvest date, not the bottling date or the best-before date.
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Harvest date: when the fresh olives were picked and pressed. This is the moment the freshly pressed olive oil clock starts.
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Bottling date: when the oil was put into the bottle. Oil can sit in steel tanks for months before bottling, so this tells you almost nothing about age.
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Best-before date: usually set 18 months after bottling, not pressing. Two oils with the same best-before date could have been harvested at a totally different timing.
Heat, light, and oxygen all work against olive oil, breaking down the very compounds that give fresh oil its peppery bite and much of its appeal. These include polyphenols like oleuropein, hydroxytyrosol, and oleocanthal - compounds we explore in more detail in our Ultimate Guide to High Polyphenol Olive Oil.
If a bottle only shows a best-before date, that's often a sign the producer doesn't want you to know how old the oil really is. The types of oil you see in the supermarket frequently blend oils from multiple harvests and countries, which is exactly why the harvest date gets left off the label - there often isn't one clean date to give.
The most polyphenol-rich, flavourful oils come from early harvest olives - picked while still green and slightly under-ripe. Because these younger olives contain less oil, early harvest extra virgin olive oil is produced in smaller quantities and rarely shows up on supermarket shelves.
This is why early harvest oils, like our own November Polyphenols Early Harvest oil, are so highly prized. Picked at the point when the olives are at their freshest, they capture more of the vibrant flavours and natural compounds that make a truly exceptional EVOO.
And that's why harvest date matters more than any best before stamp - it tells you the plain and simple truth: how old the oil inside the bottle really is.
How to tell if your olive oil is fresh
Other the lab certifications your nose and palate can also tell you most of what you need to know:
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Smell it first: Fresh olive oil should smell green and alive: cut grass, tomato leaf, herbs, sometimes apple or artichoke. If the aroma is flat the oil has started to oxidise - meaning the natural compounds that help protect its flavour and freshness are gradually being broken down.
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Taste it: Good oil should taste like something; peppery and slightly bitter, often with a sharp sensation at the back of the throat. That peppery catch at the back of your throat is the polyphenol oleocanthal at work, and it's a sign of freshness. If your oil tastes of nothing at all, that's often a worse sign than tasting "off" - it may have already lost the compounds responsible for its flavour, aroma and freshness.
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Check the texture: Swirl a spoonful. Fresh olive oil moves smoothly and coats evenly.
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Read the label - properly: Look for a specific harvest year (not just a best-before date), the region the olives came from, and ideally an acidity or polyphenol figure. Producers who are proud of their oil usually make this information easy to find.
How long does olive oil last?
Unopened and stored properly (sealed, away from heat and light), a well-made extra virgin olive oil can maintain its quality for around 12-18 months from its harvest date. After that point, its flavour, aroma and natural compounds gradually begin to fade - even if the bottle is still sealed.
Once opened, the clock speeds up rapidly. Every time you unscrew the cap, oxygen gets in and begins to affect the oil. For the best flavour and to preserve as much of its natural goodness as possible, aim to use an opened bottle within a couple of months. Keep it tightly sealed and store it somewhere cool and dark, away from direct sunlight and heat.
A bottle left next to the hob or open on a sunny windowsill will taste noticeably worse than the same oil kept in a dark cupboard with the cap on.
This is where the difference between everyday supermarket oils and early harvest, high-polyphenol oils becomes clear. Oils that start with a higher concentration of natural compounds - like our November Polyphenols oil (lab-certified at 1,200+ mg/kg by the World Olive Centre for Health in Athens) or MasWorth Family Groves (lab-certified at 965+ mg/kg) - have more of those qualities to preserve as they age.
You can see how November compares with other oils, including supermarket options, in our guide to the best high-polyphenol olive oil in the UK.
Does olive oil go bad?
Yes - but not in the way milk or meat does. Olive oil doesn't grow mould or become unsafe to eat in the way perishable foods do. What happens instead is oxidation: the fats begin to break down, flavours and aromas fade, and the polyphenols and antioxidants that make EVOO worth choosing gradually decline. It's less "spoiled" and more "past its best," in the way a cut flower wilts rather than rots.
Can you use expired olive oil?
An olive oil that has passed its best-before date isn’t necessarily spoiled or unsafe, but that doesn’t mean it will still offer the same flavour, aroma and freshness as when it was first opened. Once it's expired, you're using it purely as a neutral fat with none of the flavour you paid for. If it smells or tastes off, it's better used for practical jobs around the house, like loosening sticky labels from jars, than for cooking or dressing food.
Why most supermarket olive oil is already past its best
The oil on most supermarket shelves has usually been blended from several harvests and countries, refined for a long shelf life, and bottled without a harvest date. By the time that oil reaches a trolley, it could be a year or more past pressing - and the bottle can then sit in a warehouse and on a shelf for months longer before it’s opened.
This is why we focus on traceability, harvest dates and oils made with freshness in mind - so you know exactly what you’re getting in every bottle.
The MasWorth difference
Our olive oil comes from Greece, harvested early when the olives are still green, and the polyphenol content is at its peak. Because early harvest yields less oil per tree, production runs in small batches, and every batch is lab-tested for polyphenol content.
Every MasWorth bottle also includes clear harvest information and full traceability, so you always know exactly what you’re pouring. We also use light filtration and dark glass packaging to help protect the oil’s freshness, flavour and natural qualities from harvest to kitchen.
But freshness doesn’t stop when the bottle reaches your kitchen. That’s why we make it easy to stay stocked with fresh olive oil with our subscription service.
Choose the oil that suits your taste, from our November Polyphenols Early Harvest oil to our MasWorth Family Groves blend, and select how often you’d like deliveries. It’s a simple way to keep fresh, high-quality olive oil in your kitchen without having to remember when it’s time to reorder.
Want to learn more about November? Find out why it’s a name rather than a type of olive oil, or explore our blog for more tips on choosing and enjoying extra virgin olive oil.
Frequently Asked Questions
Does olive oil go bad?
Yes, but not in the same way as fresh foods like milk or meat. Over time, exposure to oxygen, heat and light causes oxidation, which gradually affects the oil’s flavour, aroma and freshness.
How can I find the best fresh olive oil?
The best fresh olive oil comes from producers who share clear harvest information, traceable sourcing and quality testing. If you’re looking for fresh olive oil for sale, MasWorth bottles include these details so you can see exactly where your oil comes from.
Why doesn’t my olive oil have a harvest date?
Not every producer includes one. Many supermarket oils are blended from different harvests, which makes a single harvest date difficult to provide. Oils with a clear harvest date give you a better idea of how fresh they really are.
Is bitter olive oil bad?
No. A slight bitterness and peppery sensation are often signs of fresh, high-quality extra virgin olive oil. These flavours come from natural compounds such as oleocanthal, rather than being a sign the oil has gone bad.
Should I refrigerate olive oil to keep it fresh?
You don’t have to refrigerate your oil. The best place to store olive oil is somewhere cool, dark and away from heat sources.
