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 spent bottled destroy the polyphenols and aromas that give it its flavour and health 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 damage extra virgin olive oil?
Heat damages extra virgin olive oil because it is a living product: it contains polyphenols and volatile aromas that break down under high temperatures and over time spent in the bottle. The result is a flatter oil — less aroma, less flavour, fewer health 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 taste, its scent and its properties. But it is also sensitive.
When it spends a long time in the bottle — especially if it was bottled months or even a year earlier — and is also exposed to high temperatures (as happens in some warehouses, during transport, or on supermarket shelves), those compounds begin to degrade.
The result? A flatter oil. Duller. Less aroma, less flavour… and less value.
Worth remembering
The first thing heat destroys are the polyphenols — the antioxidants responsible for 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 degraded by heat does not always look any different: the bottle can appear identical. The signs are in the smell and the taste. It loses its fresh aroma, becomes flat or slightly rancid, and the characteristic bitterness and peppery finish of a good EVOO disappear.
What makes this worrying is that it happens without you noticing. The bottle may still look the same, but what is inside is no longer, by any stretch, what it once was. Look for three signs:
- The aroma. A fresh oil smells of grass, tomato plant, freshly pressed olives. A degraded one smells flat, neutral, or faintly rancid.
- The flavour. It loses intensity and complexity. What once filled your mouth becomes something thin and unremarkable.
- The bitterness and peppery finish. That tingle at the back of the throat comes from live polyphenols. When it disappears, it is the clearest sign that the oil has suffered.
That is why appearances deceive: the eye cannot detect the damage, but the nose and the palate can.
How to store olive oil in summer
To store olive oil properly in summer, keep it somewhere cool and away from direct light, far from heat sources such as the oven or hob, avoid sudden temperature swings, and if you bought it in a large format, decant it into a small dark glass container so less air gets in each time you use it.
Perhaps you already have oil at home, bought weeks or months ago, and you are wondering whether there is anything you can do to protect it. The answer is yes. These tips are simple but genuinely effective:
- Store it somewhere cool and away from direct light. An interior pantry is better than a kitchen that gets sun or heat from appliances.
- Avoid sudden temperature changes. Moving it from a cool spot to a very warm one (or vice versa) takes its toll. Stability is better.
- Keep it away from 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 enters each time you use it.
- Do not trust how it looks. Even if it appears unchanged, a degraded oil has lost its polyphenols, antioxidants and flavour.
What do we do to make sure it reaches you in perfect condition?
At Mi Oliva Gourmet we keep the oil in the mill cellar, at a cool and constant temperature even in the height of summer, and we bottle it almost daily as orders come in. That way it reaches you freshly bottled, with its aroma, flavour and polyphenols fully 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 mill cellar, where the temperature stays cool and constant even in the middle of July.
- And we bottle it almost daily, as orders come in.
This means we can send you freshly bottled EVOO, with its aroma almost entirely intact, its fresh flavour and all its natural potency.
Can you really taste the difference with freshly bottled oil?
Yes — from the very first slice of toast. Freshly bottled oil keeps an intense aroma, a vibrant flavour and that bitterness and peppery finish that signals its polyphenols are alive. Compared to an oil that has endured months of heat, the difference is immediate: you notice it on the nose and on the palate.
When you try freshly bottled oil in July or August, you notice it the moment you open the bottle. From the very first piece of bread. And in summer, that makes all the difference.
Not every oil holds up equally well in the heat. But there are ways of doing things right. And even if they cost more, they are worth it. Especially when it is your health, your palate and your table that will receive it.
What people say when they receive it freshly bottled
⭐⭐⭐⭐⭐
'Sensational — all the flavour, all the scent and all the colour of a freshly harvested oil. Wonderful. Thank you for the quality.'
Belén Galán Herráiz · ✓ Verified purchase
⭐⭐⭐⭐⭐
'An oil with an intense aroma and flavour — you can tell it is of the highest quality. One of the best I have tasted in a very long time.'
Roberto Pérez Barquero · ✓ Verified purchase
⭐⭐⭐⭐⭐
'The quality of this oil is extraordinary. Its colour, aroma and flavour took me straight back to the oils of my childhood.'
Mikel Izeta Berastegui · ✓ Verified purchase
Freshly bottled oil,
not last year's
Direct from our mill in Puente Genil. Kept in a cool cellar and bottled the day it leaves for your home — with its aroma and polyphenols fully intact.
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Frequently asked questions about storing olive oil
Can you keep olive oil in the fridge?
It is neither necessary nor advisable for everyday use. Cold solidifies the oil and forms white flakes — harmless, they dissolve again at room temperature — but repeated cycles of cold and heat are not good for it. A cool, dark place with a stable temperature is a much better choice.
Does olive oil expire?
It does not expire in the sense of becoming dangerous, but it does lose quality over time. Ideally, use it within the months following bottling, when it still has its full aroma, flavour and polyphenols. That is why it matters so much that it is freshly bottled and not sitting in a bottle from a year ago.
How long does EVOO last once opened?
Once opened, it is best to use it within a few weeks or months. Every time you open the bottle, air gets in and oxidises the oil. A small, opaque container with a tight-fitting seal will help 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 oil's greatest enemies. Dark glass and tins both work well. What you want to avoid is plastic and clear glass exposed to direct light.
Is heat-degraded oil harmful to health?
A degraded oil is not toxic, but it loses much of its polyphenols and antioxidants — precisely what makes it healthy — and its flavour deteriorates. It will not harm you, but it no longer gives you what a good EVOO should. If you want to go deeper into what makes a great oil special, read about olive oil acidity.
Heat does not forgive everything. But if you treat your EVOO as what it is — a living, delicate product — it will reward you with every piece of bread and every dish. And if what you are looking for is to start summer with an oil that arrives freshly bottled from the mill, it is just one click away.
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