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Extra vir­gin olive oil (EVOO) is the flag­ship ingre­di­ent of the Mediterranean diet.

Its healthy prop­er­ties are the focus of hun­dreds of sci­en­tific stud­ies, while EVOO’s unique fla­vor makes it a cher­ished secret ingre­di­ent of many chefs around the world.

The Michelin-star chef Luigi Sartini, in San Marino, told Olive Oil Times ​“almost all of my recipes end up with an extra vir­gin olive oil fin­ish­ing.”

Given its sig­nif­i­cance as a high-qual­ity ingre­di­ent, more peo­ple around the world are choos­ing extra vir­gin olive oil for use at home.

Once in the kitchen, extra vir­gin olive oil must be prop­erly han­dled and stored to pre­serve its healthy char­ac­ter­is­tics and its spe­cial fla­vor over time.

Storing larger quan­ti­ties of EVOO

Oxygen is the biggest threat to extra vir­gin olive oil qual­ity. Contact with oxy­gen is the lead­ing cause of oxi­da­tion (light and heat cause oxi­da­tion too).

Some of EVOO’s most impor­tant com­po­nents, such as its polyphe­nols and toco­pherols, play a role in defin­ing its fla­vor and healthy prop­er­ties as well as in pre­serv­ing its qual­ity.

When EVOO comes into con­tact with oxy­gen, it oxi­dizes. When this hap­pens, the polyphe­nols oxi­date first, pro­tect­ing the pro­duc­t’s fatty acids.

Producers deploy a num­ber of pro­ce­dures and tech­nolo­gies to limit or even avoid con­tact with oxy­gen. They know that han­dling is cru­cial, and that is as true at home, where EVOO may be stored for months before its actual use.

High-qual­ity EVOO is often directly bought from the pro­ducer, who sells it in sealed con­tain­ers that can hold dif­fer­ent quan­ti­ties, usu­ally up to five liters.

“To pre­serve EVOO, every con­tainer, big or small, shall have to be filled up to the top and be cor­rectly sealed, to reduce as much as pos­si­ble the space avail­able for oxy­gen,” Alessandro Ceraudo, a pro­ducer in Latera, Italy, told Olive Oil Times. ​“Once opened for daily use, the can or bot­tle should always be prop­erly closed imme­di­ately after.”

The tem­per­a­ture fac­tor

EVOO is a resilient prod­uct and is eas­ily shipped by pro­duc­ers all over the world. Still, func­tional stor­age of EVOO cans and bot­tles in the home requires avoid­ing extremely low or high tem­per­a­tures.

The opti­mal tem­per­a­ture range for EVOO stor­age is between 14 ºC and 18 ºC. Such a range con­tributes to longer dura­bil­ity for the most rel­e­vant EVOO prop­er­ties. Still, many of its qual­i­ties will be safe even if tem­per­a­tures fall sig­nif­i­cantly out of that range.

Under 12 °C, EVOO might begin to show signs of solid­i­fi­ca­tion, but that will not dam­age its organolep­tic and nutri­tional qual­i­ties. Such dam­age can instead occur when tem­per­a­tures get too close to 0 °C.

On the other end of the spec­trum, higher tem­per­a­tures also lead to oxi­da­tion.

EVOO thrives in the dark

Light has a sig­nif­i­cant effect on extra vir­gin olive oil qual­ity and dura­bil­ity.

An EVOO stored in full light will quickly lose its healthy pro­file, even degrade in a mat­ter of months to the point of no longer being edi­ble.

Among the rea­sons for this is the role exerted by chloro­phyll, an EVOO com­po­nent that is trig­gered by light expo­sure. Once this hap­pens, the chloro­phyll destroys other cru­cial EVOO con­tents.

Storing EVOO in the dark guar­an­tees a dura­tion that is almost three times longer than stor­ing it in the light.

More specif­i­cally, EVOO’s healthy prop­er­ties are eas­ily pre­served in the dark and can still fully express them­selves in terms of fla­vor and health ben­e­fits even after pro­longed stor­age.

While dark glass bot­tles, bag-in-box con­tain­ers and tins remain the most pop­u­lar ways to store EVOO, some­times the prod­uct may come in trans­par­ent bot­tles.

In any such case, check when the EVOO was bot­tled and whether its color is some­what orange, which is an easy way to spot the chloro­phyll acti­va­tion.

When pur­chas­ing EVOO in trans­par­ent bot­tles, fol­low­ing the afore­men­tioned tip of pour­ing the bot­tle into var­i­ous smaller con­tain­ers will help pre­serve qual­ity.

Comparing bags, tins and bot­tles

A grow­ing num­ber of pro­duc­ers sell their EVOOs in bag-in-box con­tain­ers. The bags inside the box pro­gres­sively deflate as the prod­uct is poured out of the con­tainer, lim­it­ing the oil’s expo­sure to oxy­gen.

Bag-in-box con­tain­ers allow con­sumers to store larger quan­ti­ties of extra vir­gin olive oil safely at home for longer peri­ods. However, the bags are usu­ally made of plas­tic and are not refill­able.

Traditionally, pro­duc­ers have stored and sold their extra vir­gin olive oils in tin cans. These con­tain­ers are opaque, block­ing the harm­ful effects of light. They also min­i­mize the quan­tity of oxy­gen that enters and, given their dura­bil­ity and strength, may be eas­ily stored.

Tin cans are made of steel with an inter­nal tin lin­ing, which avoids any pos­si­ble chem­i­cal alter­ation of its con­tent. These con­tain­ers can also be used directly in the kitchen or put on a table at home.

Furthermore, it is pos­si­ble to buy tins in all sizes, but their metal­lic appear­ance is not always con­sid­ered aes­thet­i­cally pleas­ing and might lead con­sumers to choose other types of con­tain­ers.

However, glass bot­tles are the most widely used con­tainer for EVOO, which are seen as more aes­thet­i­cally pleas­ing. They are the pre­ferred method of stor­age for many high-qual­ity EVOO pro­duc­ers.

Still, glass bot­tles are sus­cep­ti­ble to light pen­e­tra­tion, which makes them well-suited for smaller quan­ti­ties of EVOO used for tast­ings or for use in the kitchen.

Given the grow­ing con­scious­ness of the dam­age caused by light, many pro­duc­ers have begun using glass bot­tles that are com­pletely coated in an opaque mate­r­ial; a solu­tion that pre­serves the option to invest in orig­i­nal and ele­gant designs.

Ceramic bot­tles are also becom­ing increas­ingly pop­u­lar because of the easy per­son­al­iza­tion they offer and the mes­sage of tra­di­tion and con­nec­tion to the ter­ri­tory inspired by ceram­ics.

While being more del­i­cate and prone to break­ing than some of the alter­na­tives, ceramic bot­tles allow for the high­est level of pro­tec­tion against light con­t­a­m­i­na­tion.

However, most extra vir­gin olive oil sold is sold in PET con­tain­ers. These bot­tles come in many dif­fer­ent shapes and sizes and may be eas­ily per­son­al­ized by the pro­ducer.

PET con­tain­ers are also quite resis­tant to trans­porta­tion and easy to han­dle. However, most of them are trans­par­ent, so they must be stored in a cool and dark place to main­tain their qual­ity.

How long can EVOO be stored?

While many coun­tries have dif­fer­ent reg­u­la­tions about EVOO, in the United States and European Union, its shelf life is 18 months.

Still, as EVOO qual­i­ties depend on many dif­fer­ent fac­tors – from the specifics of the pro­duc­tion phase to the fol­low­ing expo­sure to tem­per­a­ture, light and oxy­gen – the actual limit for its qual­ity to degrade might be sig­nif­i­cantly dif­fer­ent.

In opti­mal stor­age con­di­tions at home, olive oil will main­tain its extra vir­gin qual­i­ties for as long as two years. Consumers can tell when the oil is no longer extra vir­gin as they will begin to taste one of the main defects – ran­cid­ity, fusti­ness, winey-vine­gari­ness or musti­ness.

“A good strat­egy for those who make daily use of EVOO at home is to esti­mate the amount needed for one year of con­sump­tion and buy it accord­ingly directly from the pro­ducer,” Ceraudo said. ​“It should be bought right after the har­vest when the olives are processed and the new EVOO is pro­duced.”