When olive oil turns rancid, its fresh, fruity aroma may be replaced by a heavy smell like crayons or moldy hazelnuts. Its taste may also become slightly sour or flat. To tell whether olive oil has turned rancid, notice how its fresh, fruity, slightly bitter taste changes over time. Like butter, olive oil turns rancid as its fats gradually break down when exposed to light, heat, and oxygen. This process can be slow, so using olive oil within a reasonable time after opening and storing it properly help preserve its freshness.
What Are the Signs of Rancid Olive Oil?
Smell and taste are the most reliable ways to tell whether olive oil has turned rancid. Look for these changes:
• The fresh, fruity olive aroma changes to a smell like crayons or paint.
• The slight bitterness gives way to an unpleasant, sharp, oily taste.
• Unexpected sediment or cloudiness appears in the bottle.
• The oil leaves a rough, waxy feeling in the mouth.
• Its color changes from a vivid greenish yellow to a dull, pale shade.
What Mistakes Should You Avoid When Storing Olive Oil?
Common storage mistakes can cause olive oil to turn rancid sooner. Avoid storing it on a shelf near the stove, where it is continually exposed to heat. Do not leave it in a clear glass bottle in direct sunlight. Keep the cap tightly closed to limit contact with air. Do not assume that high-quality oil cannot spoil after opening. Leaving a large tin open and using it for years exposes the oil to air and can lead to rancidity.
Does Extra-Virgin Olive Oil Turn Rancid Faster Than Refined Oil?
The natural antioxidants in cold-pressed extra-virgin olive oil may make it more resistant to rancidity than some refined oils, but this protection is limited. Extra-virgin olive oil can also turn rancid if it is stored improperly. After opening, limit its exposure to light and air. A dark glass or tin container reduces light exposure compared with a clear bottle and can help preserve freshness.
How Long Does It Take Olive Oil to Turn Rancid?
The rate depends on how much light the bottle receives, the storage temperature, and the oil's quality when produced. A bottle kept in a cool, dark cabinet and used frequently may stay fresh for a few months, while oil left in a warm, bright place can turn rancid much sooner. Choosing a small bottle that you can use promptly instead of a large one can also help preserve freshness. Changes in smell and taste are the signs to watch for. Store olive oil in a cool, dark place with the bottle tightly closed to slow rancidity. If its smell or taste seems off, do not use it. Keep the bottle away from the stove and store it in a dark container in a cool cabinet to help preserve its quality.