We often check the expiry dates on milk or meat, but what about that bottle of cooking oil? Many of us store it in the kitchen cabinet for months, perhaps even years. So, can cooking oil expire? The short answer is: yes, although not in the same way milk "spoils," cooking oil undergoes a process called "rancidity."
First, it's important to distinguish between a "Best Before" date and an "Expiry Date." The date you see on a bottle of Nabati Cermelang is a "Best Before" date. This is our guarantee that up to that date, the oil will maintain its "Cermelang" (Brilliant) quality—its clarity, neutral taste, and nutritional content—if stored properly. Beyond that date, the oil might still be safe, but its quality will begin to decline.
What exactly is "rancidity"? Rancidity is the result of oxidation. This is a natural chemical process where the fat molecules in the oil react with oxygen in the air. This process is accelerated by oil's three main enemies, which we've discussed in a previous article: light, heat, and air. As it oxidizes, the oil's structure changes, creating new compounds that smell unpleasant (like crayons or putty) and ruin the taste of your food.
How can you tell if your oil has gone rancid, even before the "Best Before" date arrives (due to improper storage)? Use your senses. Smell it. Fresh oil like Nabati Cermelang should have a neutral aroma. If you detect a sour, stale, or sharp "off" smell, it's likely rancid. Look at the texture. Degraded oil often becomes more viscous or thick. Observe the color. An oil that should be clear might become cloudy or darker.
While a high-quality oil like Nabati Cermelang has excellent stability due to its purity, it is still a natural product with a shelf life. Always store your oil in a cool, dark place with the lid tightly sealed. And most importantly, trust your senses over the printed date. For the best, most "brilliant" cooking results, always use fresh oil.