Why Do So Many Olive Oils Come in Green Bottles?

Does the color of your bottle actually matter? Experts weigh in.

Korin Miller has spent nearly two decades covering food, health, and nutrition for digital, print, and TV platforms. Her work has appeared in Women's Health, SELF, Prevention, The Washington Post, and more.

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Cruise the condiment aisle at your local grocery store and you’ll notice a sea of green bottles: olive oil, in plastic and glass containers and from budget picks to upscale options. But why the monochrome? Dark green bottles are near synonymous with olive oil, and the answer involves a lot more than aesthetics. Here’s what’s behind that signature bottle shade, according to olive oil sommeliers and chefs.

Light is one of olive oil’s main enemies and can cause it to go rancid, says olive oil sommelier Emily Lycopolus, author of The Olive Oil & Vinegar Lover’s Cookbook. Storing olive oil in a dark green bottle helps filter out ultraviolet rays that can cause oxidation.

“Like putting sunglasses on, the dark green protects the oil from the light,” explains Emilie Berner, chef/instructor of plant-based culinary arts at the Institute of Culinary Education’s Los Angeles campus.

Light can also impact the flavor of the olive oil, interfering with its fruity taste, says Paul DiBari, chef-instructor of culinary arts at the Institute of Culinary Education’s New York City campus.

“Like putting sunglasses on, the dark green protects the oil from the light.”

But there’s more to consider than just flavor. Rancid olive oil contains free radicals, which are linked to cancer when found in high concentrations in the body, Lycopolus points out. Olive oil stored in darker bottles might also offer more health benefits. Even in a well-sealed bottle, oxidation can occur when olive oil is exposed to light alone because of its naturally-occurring chlorophyll, which converts light into oxygen. “The process of oxidation us[es] up antioxidants, so many of the healthful qualities are no longer present in a rancid or oxidized oil,” Lycopolus says.

A green bottle isn’t an indicator of better quality than other tinted glass or opaque containers.

Olive oil sommelier Susan Abranovic, founder of Susan Julia Olive Oil, explains that dark green bottles were commonly thought to offer the best protection. But, “over time, with much testing, what is understood today as ideal is a dark glass bottle.”

Still, many olive oil bottles remain green.

“Green glass is easier to find, widely produced, and offers good UV protection,” Lycopolus says. “It also doesn't require harder-to-find ingredients like cobalt, which is used to make blue glass. The majority of manufacturers create green and amber glass, so it’s readily available.”

However, any dark-tinted glass or opaque container made of ceramic or stainless steel is a great option. “They block all light and are non-reactive, unlike other metals [like iron and copper] that can oxidize and then be found in the olive oil,” Lycopolus says. “Olive oil is a sponge and soaks up whatever it's in contact with.”

When selecting olive oil, avoid plastic bottles, which are more porous than glass, ceramic, or stainless steel options and which can let in too much light. Some studies have also shown that plastic packaging can transfer microplastics to olive oil, Abranovic says.

Olive oil is essentially fruit juice, Abranovic says. “It should really be placed in the produce section, because olive[s] [are] a stone fruit.”

Olive oil starts to oxidize as soon as it's harvested, Lycopolus adds. But storing olive oil in a cool, dry place like your pantry can help prevent oxidation.

“Once olive oil is bottled, it has a shelf life of 18–24 months. And some olive oils even less,” DiBari says. Because the oil starts to break down quickly once it’s been unsealed, “you should use it within six months of opening.”

Lycopolus thinks you should try to finish your bottle even faster: It’s best to enjoy your olive oil within six weeks if you’re able “as the open air and oxygen in the bottle will encourage it to go rancid faster.”

Olive oil sommeliers and chefs have a few recommendations for selecting a quality olive oil.

But if you happen to spot a fresh and interesting-looking bottle of olive oil in an opaque or stainless steel bottle — not a green one — try it with confidence.