Grape seed oil is a versatile ingredient in the kitchen. It has a mild taste, and can be heated to high temperatures when cooking. Although grape seed oil can probably be found in the majority of kitchens, how many people really know the shelf life of this cooking oil? Can grape seed oil go bad, and how should it be stored?
Can Grape Seed Oil Go Bad?
Grape seed oil, like all cooking oils, can actually go bad. While it’s highly unlikely that mold or bacteria will grow in the oil, it can still spoil in the form of oxidation. Oxidation occurs when the oil is exposed to oxygen, and degrades the quality of the oil, eventually turning the oil rancid. Rancid oil has lost most of its health benefits, and can actually have a negative impact on health when consumed over extended periods of time.
While oxidation will occur eventually no matter what, proper storage can help to slow this process, and extend the shelf life of grape seed oil.
What Is the Shelf Life of Grape Seed Oil?
When properly stored, an unopened bottle of grape seed oil will have a shelf life of up to three months after the printed expiration date. If the unopened bottle is refrigerated, the shelf life is extended to up to six months past the expiration date.
Of course, once the bottle is opened, the exposure to air, heat and light will begin to oxidize the oil and the shelf life at room temperature will reduce to three months past the date of opening. Refrigerated, grape seed oil will last about six months past the date it was opened.
Keep in mind that exposure to light, heat and oxygen can increase the rate at which grape seed oil spoils, so it’s always best to check the oil for signs of spoilage before using.
How to Tell Grape Seed Oil Has Gone Bad
The easiest way to tell if grape seed oil has gone bad, is to smell the oil. Rancid oil will have an unpleasant, slightly sour odor and taste. Any type of unpleasant odor indicates that the oil has gone bad and should not be consumed.
Image used under Creative Commons from Taras Kalapun
If you store your grape seed oil in the refrigerator, or any pretty cold environment, you may notice that the oil becomes cloudy or even forms solid chunks. This is a completely normal reaction to the cold and does not indicate spoilage. Simply thawing the oil will return its consistency to normal.
How to Store Grape Seed Oil
Grape seed oil should be stored in a tightly sealed container, and kept in a cool dark place. The best storage vessel is a dark colored or opaque bottle. If you can, try to buy grape seed oil that already comes in a container like this. If you’ve bought grape seed oil that came in a clear glass or plastic bottle, that is fine, but you should be extra careful about keeping the bottle away from light sources.
Storing grape seed oil in the refrigerator can greatly extend the shelf life, as this environment is cool and mostly dark (until the door opens, at least!). Try to store oil at the back of the refrigerator, where it will be exposed to the fewest temperature changes, as temperature fluctuations can increase the chance of oxidation.
Finally, freezing grape seed oil is not recommended, as this will not increase the shelf life of the oil dramatically. Freezing oil will also cause the oil to become less stable when at room temperature. If you accidentally freeze oil, you should thaw it at room temperature and try to use the oil within a week. Re-freezing oil is not recommended.