Don’t Panic

You pull your olive oil out of the shipping box on a cold morning and notice it’s gone cloudy, thick, or even completely solid. Your first instinct might be to wonder if something went wrong. Nothing went wrong. Cloudiness and solidification in olive oil are natural physical responses to cold temperatures.

In fact, the way olive oil behaves in the cold comes down largely to its natural fat composition. Different olive oils can behave very differently, which is why one bottle might turn cloudy while another stays perfectly clear at the same temperature.

Why Seed Oils Don't Solidify

Different edible oils have very different fatty acid and triglyceride profiles, so they naturally behave differently when chilled.

Commercial oil processing influences cold-temperature behavior. Most refined oils undergo a process called winterization, in which waxes or triglycerides are removed by filtration. This helps keep the finished oil clear at lower temperatures.

Winterization is part of a broader refining process that also includes steps such as:

• Degumming — removing phospholipids and gums
• Neutralization — reducing free fatty acids
• Bleaching — removing pigments and other compounds using adsorbent materials
• Deodorization — using steam and heat to remove unwanted aromas and flavors

Extra virgin olive oil is different. It is produced mechanically from olives without chemical refining or deodorization. That allows it to retain the natural aromas, flavors, phenolic compounds, pigments, and other minor components that make freshly produced extra virgin olive oil so distinctive.

Why Does Olive Oil Solidify?

Olive oil is made primarily of triacylglycerols, often shortened to TAGs. These are molecules made of three fatty acids attached to glycerol. Olive oil contains many different TAGs, and they don’t all crystallize at the same temperature.

As olive oil gets colder, the higher-melting TAG fractions begin to crystallize first. Tiny crystals form throughout the oil, making it appear hazy or cloudy. As the temperature continues to fall, more of the oil crystallizes, causing it to become thick, semi-solid, and eventually solid.

The exact temperature varies considerably from one olive oil to another depending on olive variety, growing conditions, harvest timing, and the oil’s particular fatty acid and triglyceride composition.

Extra virgin olive oil may begin developing visible cloudiness somewhere around 60°F, while more substantial crystallization often occurs as temperatures approach refrigerator temperatures. But there is no single temperature at which all olive oils become cloudy or solid.

The Dr. Oz Refrigerator Test — And Why It’s Wrong

You may have seen the claim — popularized years ago by Dr. Oz — that you can verify whether your olive oil is “real” extra virgin by putting it in the refrigerator. If it solidifies, the story goes, it’s authentic. If it stays liquid, it’s fake or adulterated.

This test is not scientifically valid.

The problem is that crystallization depends heavily on olive variety, harvest timing, growing conditions, and the oil’s particular triglyceride and fatty acid composition. None of those factors reliably tell you whether an olive oil is authentic or whether it qualifies as extra virgin.

A perfectly genuine extra virgin olive oil may stay relatively fluid in the refrigerator. Another may become cloudy, chunky, or nearly solid. An adulterated oil could also solidify if its fat composition happens to encourage crystallization.

The refrigerator test tells you something about the physical chemistry of the oil. It tells you almost nothing about its quality or authenticity.

What Causes the Cloudiness Specifically?

Cold-induced cloudiness comes primarily from crystallization of the oil’s triglycerides, with natural waxes potentially contributing as well.

• Triacylglycerols crystallizing — this is the primary cause. As temperatures fall, higher-melting TAG fractions begin forming microscopic crystals. Those suspended crystals scatter light, creating the cloudy, hazy, or sometimes chunky appearance you see in cold olive oil.
• Natural waxes crystallizing — olives naturally contain small amounts of waxes, primarily from the skin of the fruit. These waxes can also crystallize at low temperatures and may contribute to haze or sediment in some oils.

Unfiltered olive oils may sometimes appear cloudier because they also contain tiny suspended olive particles and moisture droplets. But filtration alone does not determine whether an olive oil will crystallize in the cold. The oil’s natural triglyceride composition plays the much larger role.

Should You Refrigerate Olive Oil?

This is one of the most common questions we get, and the answer is: you don’t need to, but you certainly can.

The major enemies of olive oil are heat, light, oxygen, and time. Cold, by comparison, dramatically slows the chemical reactions responsible for oxidation.

Refrigeration may cause some olive oils to cloud, thicken, or partially solidify, but this does not mean the oil has been damaged. Once the oil warms back to room temperature, those crystals melt and the oil becomes clear and pourable again.

For everyday use, refrigeration usually isn’t necessary if your olive oil is stored properly:

• Keep it in a cool location
• Protect it from direct sunlight and excessive light
• Keep it away from heat sources such as the stove or oven
• Keep the cap tightly sealed between uses
• Buy an amount you can reasonably use while the oil is still fresh

If you have an opened bottle that you know you won’t finish for several months, refrigeration can be a perfectly reasonable storage strategy. Cold slows oxidation, which is one of the primary causes of olive oil losing freshness and eventually becoming rancid.

Can You Freeze Olive Oil?

Freezing is technically a way to slow the aging of olive oil when you want to preserve it for an extended period. At normal freezer temperatures, olive oil will solidify completely. Once brought back to room temperature, it will melt and return to its normal liquid state.

Research examining extra virgin olive oil stored at freezing temperatures has found that very cold storage can preserve important chemical and sensory characteristics extremely well by dramatically slowing oxidation.

But again, for daily use, it's simply not necessary.

A Quick Reference

• Cloudy or hazy in cool temperatures — normal crystallization
• Small white particles or crystals — normal, particularly as the oil gets colder
• Thick or semi-solid in the refrigerator — normal and reversible
• Stays liquid in the refrigerator — also normal depending on the oil
• Fully solid in the freezer — normal
• Returns to liquid when warmed — exactly what should happen
• Stale, waxy, crayon-like, or rancid aroma — oxidation, not cold damage

Fresh Oil, Stored Right

The best olive oil in the world won’t stay that way forever. Olive oil is the freshly extracted juice of a fruit, and from the moment it is produced, time begins working against it.

Our oils are milled from California-grown olives, stored temperature-controlled, bottled at our family mill, and shipped directly to you.

Whether you reach for our bold Robust Extra Virgin Olive Oil or our smooth Buttery & Sweet Extra Virgin Olive Oil, don’t worry if winter weather changes the way it looks.