Summer and Your Olive Oil: What Almost Nobody Tells You
📅 Updated May 2026 · Reading time: 6 minutes
Quick answer
Summer heat degrades extra virgin olive oil even with the bottle sealed: high temperatures and time in the bottle destroy the polyphenols and aromas that give it its flavour and properties. To protect it, store it somewhere cool and dark, away from heat sources, avoid sudden temperature changes, and transfer it to a small opaque container if you bought it in a large format.
In this article
Why does heat spoil extra virgin olive oil?
Heat spoils extra virgin olive oil because it's a living product: it contains polyphenols and volatile aromas that degrade under high temperatures and over time in the bottle. The result is a flatter oil — less aroma, less flavour, fewer properties — even though the bottle looks exactly the same.
EVOO is packed with natural compounds — such as polyphenols and volatile aromas — that give it its flavour, its aroma and its properties. But it's also sensitive.
When it spends a long time in the bottle — especially if it was bottled months ago, or even the year before — and then gets exposed to high temperatures (as happens in some warehouses, during transport or on supermarket shelves), those compounds start to break down.
The result? A flatter oil. Duller. Less aroma, less flavour… and less value.
Worth remembering
The first thing heat destroys is the polyphenols — the antioxidants behind that peppery catch in the throat and much of the oil's health benefits. If you want to understand why they matter so much, we explain it here: Polyphenols in EVOO: what they are and why they matter.
How can you tell if your oil has been damaged by heat?
An oil damaged by heat doesn't always look any different: the bottle can appear identical. The signs are in the smell and the taste. It loses its fresh aroma, turns flat or slightly rancid, and the peppery, bitter notes typical of a good EVOO disappear.
What makes this worrying is that it happens without you noticing. The bottle may look the same, but what's inside is no longer anything like what it was. Watch for three signs:
- The aroma. A fresh oil smells of grass, tomato leaves, freshly crushed olive. A degraded one smells flat, neutral or slightly rancid.
- The flavour. It loses intensity and complexity. What once filled the mouth fades into something vaguely oily and forgettable.
- The pepper and bitterness. That tingle at the back of the throat comes from live polyphenols. When it disappears, it's the clearest sign that the oil has suffered.
That's why appearances deceive: the eye won't catch the damage, but the nose and palate will.
How to store olive oil in summer
To store olive oil properly in summer, keep it somewhere cool and away from direct light, well away from heat sources such as the oven or hob, avoid sudden temperature changes, and if you bought it in a large format, transfer it to a small dark glass bottle so that less air gets in each time you use it.
Maybe you already have oil at home, bought weeks or months ago, and you're wondering whether there's anything you can do to protect it. The answer is yes. These tips are simple but very effective:
- Store it somewhere cool and away from direct light. An interior pantry is better than a kitchen with sun or heat from appliances.
- Avoid sudden temperature changes. Moving it from a cool spot to a very warm one (or back again) takes its toll. Stability is better.
- Don't leave it near the oven, hob or microwave. Ambient heat affects it even without direct contact.
- If you bought a large format, decant it into small bottles. Dark glass if possible. That way less air gets in every time you use it.
- Don't trust appearances. Even if it looks the same, a degraded oil has lost polyphenols, antioxidants and flavour.
What do we do to make sure it reaches you intact?
At Mi Oliva Gourmet we keep our oil in the mill cellar, at a consistently cool temperature even in the height of summer, and we bottle it virtually every day as orders come in. That way it reaches you freshly bottled, with its aroma, flavour and polyphenols intact.
While most brands bottle their entire production between November and January — sometimes before they even have the orders — we do exactly the opposite:
- We keep the oil in the Almazara cellar, where the temperature stays cool and constant even in the middle of July.
- And we bottle virtually every day, as orders come in.
That lets us send you freshly bottled EVOO, with its aroma almost entirely preserved, its flavour fresh and all its natural power intact.
Can you really taste the difference with freshly bottled oil?
Yes — and you notice it from the very first slice of bread. A freshly bottled oil holds an intense aroma, a vibrant flavour and that peppery, bitter edge that signals live polyphenols. Compared with an oil that has endured months of heat, the difference is immediate, both on the nose and on the palate.
When you try a freshly bottled oil in July or August, you notice it the moment you open the bottle. From the first piece of bread. And in summer, that makes all the difference.
Not all oils hold up equally well in the heat. But there are ways of doing things properly. And even if they cost more, they're worth it. Especially when it's your health, your palate and your table on the receiving end.
What customers say when it arrives freshly bottled
⭐⭐⭐⭐⭐
'Sensational — all the flavour, all the aroma and all the colour of a freshly harvested oil. A real treat. Thank you for the quality.'
Belén Galán Herráiz · ✓ Verified purchase
⭐⭐⭐⭐⭐
'An oil with an intense aroma and flavour — you can tell it's of the highest quality. One of the best I've tasted in a long time.'
Roberto Pérez Barquero · ✓ Verified purchase
⭐⭐⭐⭐⭐
'The quality of this oil is spectacular. Its colour, aroma and flavour brought back memories of the oils I knew as a child.'
Mikel Izeta Berastegui · ✓ Verified purchase
Freshly bottled oil,
not last year's
Direct from our Almazara in Puente Genil. Kept in a cool cellar and bottled the day it leaves for your home — with all its aroma and polyphenols intact.
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Frequently asked questions about storing olive oil
Can you keep olive oil in the fridge?
It's neither necessary nor advisable for everyday use. Cold solidifies the oil and creates harmless white flakes — they dissolve again at room temperature — but repeated swings from cold to warm don't do it any good. A cool, dark spot with a stable temperature is a far better option.
Does olive oil expire?
It doesn't expire in the sense of becoming unsafe, but it does lose quality over time. Ideally, you should use it within the months following bottling, when it still has all its aroma, flavour and polyphenols. That's why it matters so much that it's freshly bottled and not something that was put in a bottle a year ago.
How long does EVOO last once opened?
Once opened, it's best to use it within a few weeks to a few months. Every time you open the bottle, air gets in and oxidises the oil. A small, opaque container with an airtight seal helps it stay in good condition for longer.
Is dark glass or a tin better for storing oil?
Both protect against light, which is one of the oil's biggest enemies. Dark glass and tins both work well. What you should avoid is plastic and clear glass exposed to direct light.
Is heat-degraded oil bad for your health?
A degraded oil isn't toxic, but it loses much of its polyphenols and antioxidants — precisely what makes it healthy — and its flavour suffers. It won't harm you, but it no longer gives you what a good EVOO should. If you'd like to go deeper into what makes a great oil special, read about olive oil acidity.
Heat doesn't forgive everything. But if you treat your EVOO for what it is — a living, delicate product — it will reward you with every slice of bread and every dish. And if what you're after is a summer oil that arrives freshly bottled straight from the mill, it's just a click away.
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