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Costco’s Kirkland Signature brand organic extra virgin olive oil not only made our list of 14 best finishing olive oil brands, but it’s also recommended by chef Samin Nosrat. Encompassing olives from around the Mediterranean, this olive oil has a rich and complex taste that stands up to famous name brands. However, the downside to Costco’s Kirkland Signature brand olive oil is its plastic packaging.
Costco’s plastic bottled olive oil may be lighter and less expensive than glass-bottled competitors, but health and olive oil experts alike argue that you should never store olive oil in plastic bottles. Olive oil is a fairly delicate fat that requires various climatic conditions for optimal storage even in glass bottles. But, it’s actually dangerous to store olive oil in plastic. After a period of time in plastic the oil will corrode the container which will then leach back into the olive oil. Consequently, you could be ingesting microplastics with every drizzle, toss, or sizzle, despite how deceptively good the olive oil might taste. While the study of microplastics in diet is still limited to petri dishes and test tubes, studies cited by Healthline indicate that they present dangers to the health of many internal organs. Furthermore, one of the easiest ways to avoid exposure to microplastics is by limiting the amount of plastic-packaged products you buy.
What to look for when buying olive oil
While olive oil in plastic bottles will last between 3 to 6 months unopened before it starts to degrade, how many months has the olive oil been sitting on Costco’s shelves before you purchase it? You might have way less time than you might think to use up all that olive oil before those negative consequences take effect. This brings up another tip we received from Thomas Keller, who recommends buying olive oil in small quantities. Small batch olive oil is easier to use up while it’s still fresh and flavorful. Not only is Kirkland Signature organic extra virgin olive oil packaged in plastic, but those bottles are also a fairly giant 2 liters in size.
Ideally, what you should look for when buying olive oil is small batch glass bottled brands. Glass doesn’t react with olive oil and allows for a much longer shelf life than plastic. Dark colored glass is optimal as it helps shield the olive oil from light which speeds up degradation. Glass is also an ideal material for temperature control as it’s a better insulator than plastic. Hotter temperatures also lead to the degradation of quality and flavor. So, in addition to glass bottles, you should store a glass bottled olive oil in a cool, dark pantry. If you’re looking for a tasty, high-quality olive oil in a dark glass bottle, we recommend California Olive Ranch Olive Oil, which is available on Amazon. It was one of our favorite olive oil brands from a taste test.
