Reusing cooking oil multiple times is a common practice in many kitchens to save costs. A high-quality oil like Nabati Cermelang indeed has superior heat stability, making it more durable than ordinary oils. However, it is crucial to remember that all cooking oils have a lifespan. Using oil that has "broken down" or degraded will not only ruin the flavor of your food but can also potentially form compounds that are harmful to your health. Knowing when to stop and replace your oil is key to cooking that is both delicious and healthy.
The first and most easily recognizable sign is the color becoming dark and cloudy. New Nabati Cermelang oil should be clear and clean golden. After several uses, burnt food particles and the oxidation process will turn the oil dark brown and murky. If the oil is so opaque that you cannot see the bottom of the pan, it's a definite sign to replace it.
The second sign is a change in texture: the oil becomes thick or foamy. Pay attention when you pour the oil. If it flows more slowly and feels more viscous (thicker) than usual, it's a sign its chemical structure has changed. Another danger sign is if the oil produces excessive foam or bubbles on its surface when heated, even before you've added any food.
The third and fourth signs can be detected before you even cook: smell and smoke. Your nose is a great quality sensor. Fresh, pure oil should have a neutral odor. If your oil starts to emit a rancid, sour, fishy, or any other "off" smell, do not hesitate to discard it. Furthermore, watch its smoke point. If your oil starts smoking very quickly at a much lower temperature than normal (even though Nabati Cermelang has a high smoke point), it means the oil has degraded and is unfit for use.
The fifth sign, and the most detrimental, is a change in the food's taste. If all your fried foods—whether it's tempeh, chicken, or banana—start to have the same residual "aftertaste," usually slightly bitter or rancid, it means the oil is already contaminating your food. Don't sacrifice the "brilliant" taste of your dish. As a general rule, avoid using the same oil for deep-frying more than 3-4 times, especially if it was used for breaded or high-protein foods.