Everything You Need to Know About Olive Oil
Walk down the olive oil aisle of any decent supermarket and you will find bottles labelled extra virgin, pure, light, cold-pressed, first cold-pressed, and various combinations thereof. The price range spans an order of magnitude. The labelling tells you almost nothing useful. This is partly a regulatory problem and partly a marketing one, and the result is that most people buy the wrong olive oil for the wrong purpose and wonder why their cooking does not taste as good as it should.
What the grades actually mean
Extra virgin olive oil
Extra virgin is the highest grade and the only one worth buying for finishing — drizzling over finished dishes, making vinaigrettes, dipping bread. The term has a legal definition: the oil must be produced by mechanical means only (no chemical solvents), have a free acidity of less than 0.8% (a measure of oil degradation), and pass organoleptic tests for taste and smell. It must taste of olives, have some bitterness (a sign of polyphenols, which are antioxidants), and have no defects.
In practice, the legal definition is policed inconsistently, and some bottles labelled extra virgin do not meet the standard. Which brings us to the most important rule: if it tastes flat, bland, or stale, it is not good extra virgin olive oil regardless of what the label says.
Virgin olive oil
Also produced by mechanical means but with slightly higher acidity (up to 2%) and some organoleptic defects are permitted. Rarely seen on retail shelves in most markets. Acceptable for cooking, not for finishing.
Olive oil (also sold as "pure" olive oil)
A blend of refined olive oil (produced with heat and chemicals, then deodorised and decolourised) and a small amount of virgin oil for flavour. It has a neutral taste, a high smoke point, and no appreciable nutritional benefit over other refined oils. Cheap, stable, and useful for high-heat cooking where the flavour of extra virgin would be wasted.
"Light" olive oil
Refers to the flavour and colour, not the calorie content — all olive oils have essentially the same calorie count. Light olive oil is a heavily refined product with a very neutral flavour and high smoke point. It is marketed to people who want olive oil's perceived health halo without olive oil's taste. Ignore it.
The smoke point myth
A persistent myth holds that extra virgin olive oil should not be used for cooking because its smoke point is too low and it becomes harmful when heated. This is wrong in several important ways.
The smoke point of extra virgin olive oil ranges from about 185 to 210°C depending on quality and acidity — well above typical sautéeing temperatures (around 150 to 175°C). More importantly, smoke point is not a reliable indicator of when an oil becomes harmful. Oxidation — the actual chemical degradation that produces potentially harmful compounds — is more relevant than smoke point, and extra virgin olive oil is remarkably stable under heat due to its high monounsaturated fat content and antioxidant polyphenols.
Studies testing oils under cooking conditions consistently find that extra virgin olive oil performs well — often better than more refined oils that have higher smoke points but lower antioxidant content. Cooking with good extra virgin olive oil is not just acceptable; for most stovetop tasks, it is preferable.
Finishing versus cooking oil
That said, there is a practical and economic argument for using two different olive oils. A bottle of good extra virgin olive oil that costs £20 and that you use for finishing dishes, dressings, and raw applications where flavour is paramount, and a bottle of less expensive olive oil for everyday cooking. The expensive oil delivers its flavour where it can be appreciated; the inexpensive one does its job without waste.
If budget is a constraint, one good bottle of extra virgin olive oil used for everything is fine. The flavour contribution of oil in sautéeing is modest compared to its use raw. Compromise on the cooking oil before you compromise on the finishing oil.
How to evaluate olive oil
Good extra virgin olive oil should have a fresh, grassy, or fruity smell. It should taste of olives, have clear bitterness, and a peppery sensation in the back of the throat — that burn is caused by oleocanthal, an anti-inflammatory compound, and is a reliable indicator of quality and freshness. An oil that is flat, tasteless, or smells of crayons or old fat is degraded, regardless of price.
Pour a small amount into a glass (a shot glass works) and cup your hands around it to warm it slightly. Sip it and let it coat your mouth. The bitterness should come almost immediately. The pepper burn should develop at the back of your throat 5 to 10 seconds later. If neither is present, the oil is past its prime.
Storage and shelf life
Olive oil degrades through exposure to light, heat, and air. Buy it in dark glass or tin rather than clear glass, store it away from the stove and sunlight, and use it within two months of opening. The harvest date — not the best-before date — tells you how fresh it is. Olive oil is harvested in autumn and winter, and the best oils reach market within a few months of harvest. An oil produced in November 2025 will be at its peak through mid-2026 and acceptable through the following year.
The best-before date on most bottles is set 18 to 24 months from production, which means an oil can be technically within date but already past its flavour peak. Trust your nose and your palate over the label.
