What is the best way to store extra virgin olive oil?

Introduction

Not all oils are created equal, and extra virgin olive oil (EVOO) is no ordinary oil. EVOO is a truly special, pure natural product packed with organic compounds like healthy fatty acids, vitamin E, and polyphenols (a unique form of more than 30 different antioxidants), all of which are important for your health. These valuable fatty acids, vitamins, and antioxidants make your EVOO healthy, but also susceptible to spoilage.

Fortunately, there are several things you can do to prevent your EVOO from spoiling unnecessarily quickly. This article, based on scientific research and practical experience, will explain how best to store your EVOO to prevent spoilage as long as possible and keep your valuable EVOO fresh for longer.

No time or desire to read everything? Extra virgin olive oil stays healthy and flavorful for the longest time if you store it in a cool, dark place and tightly sealed, possibly even in the refrigerator or freezer for a longer shelf life.

1. What can't olive oil tolerate?

As mentioned, EVOO is a natural product, and as everyone knows, natural products like fresh vegetables, milk, deli meats, etc., spoil quite quickly in (UV) light, air (oxygen), and heat. For example, leave deli meats and a glass of milk in the warm sun, and within a few hours you'll want to stop eating them. Vacuum-seal the product and store it in a cool place, and it will stay fresh for days or weeks. EVOO is no different. You should protect EVOO as much as possible against:

• Light activates chlorophyll (a green pigment) → this accelerates oxidation (the breakdown of biological bonds), causing the loss of polyphenols and antioxidants. EVOO in a clear bottle on a sunny windowsill can go rancid and turn orange within a few days.
• Air (oxygen). As soon as the bottle is opened, the oil reacts with oxygen. This process (oxidation) causes chemical reactions that damage fatty acids, so the oil becomes rancid over time and its quality deteriorates.
• Heat accelerates all these processes → the warmer they are, the faster the healthy substances break down.

All three accelerate the spoilage process, where healthy antioxidants break down and turn into oxidants. Health benefits, flavor, and aroma deteriorate.

That's why it's important to always store your olive oil in a dark, well-sealed, and cool place : this way, both flavor and healthiness will be preserved for the longest time.

2. How long can you keep olive oil?

Time is the fourth enemy of EVOO. As with all fresh, natural products, quality deteriorates over time. However, how you store your EVOO significantly impacts its quality and how long it stays fresh and healthy.

Our guideline is, provided it is stored cool (12 – 21 degrees) and in a dark place :

• Unopened bottle (low oxygen): preferably before the best-before date. In the EU, premium EVOO has a best-before date of 18 months after bottling .
• After opening (more contact with oxygen): Use the oil within 3-4 months . The fresher, the better. The closer it is to its best-before date, the faster your oil will deteriorate.

If you store the bottle in a cool, dark and sealed place, your beautiful olive oil will last longer.

3. Store extra virgin olive oil in a cool place

Cool storage refers to temperatures between 12 and 21 degrees Celsius. A little higher, in summer, won't spoil your EVOO immediately, but it will negatively impact its shelf life. Therefore, avoid storing your EVOO near a heater, next to the stove, on the extractor hood above the stove, or on the windowsill near the kitchen window, for example.

Can you store extra virgin olive oil in the refrigerator?

Is it a good idea to store your premium EVOO in the refrigerator? The answer is: Yes, there are advantages, but also a few, relatively minor, disadvantages.

Benefits of storing in the refrigerator

• Longer shelf life: At lower temperatures, oxidation occurs noticeably slower. Polyphenols—the healthy compounds in olive oil—are preserved longer at lower temperatures (substantiated by this study published in the Journal of Agricultural and Food Chemistry , which examines the stability of phenols at different temperatures).
• Extra protection: the oil is better protected against heat and light, two important factors that affect its quality.

Disadvantages of storing in the refrigerator

• Cloudy & solidifying: At a refrigerator temperature between 4 and 7 degrees Celsius, premium EVOO will become slightly cloudy over time. It will look like flakes floating in the air. If you wait a little longer, your EVOO will become a bit more viscous. This makes it a bit harder to pour, but this is perfectly normal for good-quality EVOO and doesn't affect its quality. The cold actually benefits the quality. The flakes and the viscosity will disappear once the EVOO returns to room temperature.
• Taste: Prolonged cooling can slightly affect the smell and taste. However, most people will barely notice the difference.

Why does olive oil solidify in the refrigerator?

EVOO is largely composed of oleic acid, a fatty acid that solidifies around 6–10°C. That's why you might see clumps or flakes when the bottle is refrigerated, or when you receive your order when it's cold outside. Return the bottle to room temperature, and the oil will become clear and liquid again within a few hours.

Can you freeze olive oil?

Yes! Absolutely. We've found at least two studies ( one here on the ScienceDirect website and one here on Springer Nature Link ) that show that you can indeed freeze EVOO for extended periods. Even after thawing for 12-18 months, there's almost no difference in quality.

The conclusions of these studies are:

• ScienceDirect: Even after 18 months, frozen EVOOs showed a superior quality profile compared to those stored at room temperature. The aroma profile also remained stable after 12 months of freezer storage. Differences in aroma and flavor profile were negligible.
• The second study also concludes that freezing at -20°C helps preserve the taste, aroma and healthy components of premium extra virgin olive oil for much longer than at room temperature. After thawing, there is hardly any difference with fresh oil: the taste and nutritional value remain largely intact.

If you want to store olive oil for a longer period of time without loss of quality, you can freeze EVOO.

Practical advice

• Daily use: Store your bottle closed in a dark place, away from heat. Use within 3 or 4 months.
• Stock bottle or bulk container: Store in a dark and especially cool place, for example, in the cellar or refrigerator. Fill a smaller bottle for use in the kitchen and on the table.
• If you plan to store your EVOO for longer than six months, consider freezing it.

4. Why EVOO is often packaged in a dark bottle

Light is EVOO's number one enemy. Because the valuable natural polyphenols, chlorophyll, and vitamins are sensitive to (UV) light, premium EVOO is almost always packaged in a dark bottle that blocks out light. This keeps your EVOO fresher for longer.

It's not wise to buy a bottle of olive oil that's packaged in a clear bottle. EVOO can't withstand (UV) light, and you never know how long that bottle has been exposed to sunlight. Chances are, even though the oil is new, it's already gone rancid in the bottle.

Some producers choose to package their premium EVOO in a beautiful, yet transparent glass bottle. It looks really nice! As long as it's not exposed to daylight, this olive oil can still be good. Tip: keep it in a kitchen cupboard and only bring it out when you have guests and want to show off the bottle.

On a holiday in Greece, I saw various types of olive oil in glass bottles and vials displayed in the blazing Greek sun at the many souvenir shops. This oil, regardless of the brand, with or without herbs, etc., becomes completely rancid and inedible after a day or two in the sun.

Always choose a dark bottle. However, even a dark bottle shouldn't be stored in direct daylight: UV light can still cause damage ( See an article in the Olive Oil Times here ). A kitchen window is definitely not an ideal place to store your valuable EVOO.

5. The benefits of Bag-in-Box (BIB) packaging

Premium EVOO is increasingly being packaged in a bag-in-box. This is a bag with a tap inside a cardboard box. Many are familiar with this from often cheaper wines. However, bag-in-box packaging extends shelf life better than glass or cans, because air and light are completely excluded. This packaging therefore offers several important advantages:

1. Light protection. The cardboard box blocks 100% of the light.
2. Oxygen protection. The inner bag shrinks as you drain the oil, preventing air from entering. This keeps the oil fresher for much longer than in a bottle that's constantly being opened.
3. Longer shelf life. Scientific tests show that oil in a bag-in-box retains its polyphenols and flavor up to four times longer than in glass.
4. Easy to use. A tap makes it easy to pour small amounts without spilling.
5. More sustainable. Cardboard and bags are often more recyclable and lighter to transport than glass. This results in a 60% lower carbon footprint than glass.

And such a beautiful traditional tin?

A tin can may look nice but it does not improve its shelf life.

After 80 days at 21.5 degrees Celsius, EVOO in a tin had deteriorated to such an extent that it no longer met EVOO standards. In other words, the olive oil had become sour. According to European legislation, EVOO may contain a maximum of Contains 0.8% free fatty acids, expressed as oleic acid. The lower this percentage, the better the quality. As this percentage increases, the oil will increasingly smell musty and become somewhat rancid.

At a temperature of 36.5 degrees Celsius, the canned oil was already no longer EVOO after 60 days. See an article in the Olive Oil Times here. on this topic, with reference to the study.

A dark bottle is better, and even better is a bag-in-a-box. The same study showed that EVOO in a bag-in-a-box could still be classified as extra virgin olive oil after 120 days of storage at 21.6 degrees Celsius (room temperature). Even after 80 days at a temperature of 36.5 degrees Celsius, the oil remained EVOO-quality.

EVOO in a bag-in-box can be kept fresh for much longer.

6. Summary: the 5 golden rules

Conclusion

Extra virgin olive oil stays healthy and flavorful for the longest time when stored in a cool, dark, and airtight container. Use within a few months of opening, but always by the best-before date, and always trust your senses. This way, you'll fully enjoy the unique flavor and health benefits of this liquid gold.

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References:

• Storage Temperature's Big Impact on Shelf Life of High-Phenolic Olive Oils
• Stability of Virgin Olive Oil Phenolic Compounds during Long-Term Storage (18 Months) at Temperatures of 5–50 °C
• Impact of Extra-Virgin Olive Oil Storage Conditions on Phenolic Content and Wound-Healing Properties
• Overall quality evolution of extra virgin olive oil exposed to light for 10 months in different containers
• Extra Virgin Olive Oil Shelf Life
• Olive Oil Food Packaging and Shelf Life
• Effect of freezing, fast-freezing by liquid nitrogen or refrigeration to preserve premium extra virgin olive oil during storage
• The freezing process helps to preserve the quality of extra virgin olive oil over time: A case study up to 18 months
• The Effect of Storage Conditions on Extra Virgin Olive Oil Quality (PDF)