Using a new batch of oil to fry our food each time our cooking requires frying isn't only expensive but almost impracticable. Come on! What happens to the oil from last night's frying? Reuse of oil in frying has been a steady practice in most homes. This practice has lead to the question of the safety in oil reuse. So, here we go!
Oil choice is crucial to making a deep fry work. Every oil has a specific smoking point, the temperature where the oil starts breaking down and starts, well, smoking. Frying occurs at high temperatures, therefore, the use of oils with high smoking points which won't break down easily is key. These oils include canola, coconut, palm, peanut, or vegetable oils. The two major reasons why oil reuse is frowned at are:
* Smoke Point In general, vegetable oils have higher smoke points than animal fats, and refined oils have higher smoke points than unrefined oils. Each time you use oil, its smoke point drops. The usual deep-frying temperature is 375 degrees Fahrenheit. If oil has a smoke point just above that, its smoke point will be too low to use again. Refined peanut, soybean and safflower oils have high smoke points at 440, 495 and 510 degrees Fahrenheit, respectively. Extra light olive oil has a high smoke point at 468 degrees Fahrnheit, but is usually more expensive. If well-strained, properly stored and not overheated on first use, these oils should be safe to reuse.
Bacteria and Free Radicals Bacteria feeds on food particles left in the oil if not properly strained and stored. Unrefrigerated oil becomes anaerobic and leads to the growth of Clostridium botulinum, which causes botulism, a potentially fatal food poisoning. Refrigerating or freezing oil retards bacterial growth. Rancid -- meaning old and stale -- oil contains free radicals, molecules that can damage cells and lead to increased cancer risk, as well as affect the quality of your food.
Most people just toss the frying pan containing the oil in a cupboard, oven or somewhere until the next use which isn't ideal. If reuse of oil is in mind, certain steps are to be followed to ensure the safety of the oil and eventually the human body (What you eat makes or mar you. I know, it is that serious). You might want to follow these simple steps.
1. Carefully maintain the temperature of the oil to prevent the food from getting too soggy (when the oil is too cold) or blitzed on the outside and raw on the inside (when the oil is too hot), and to also preserve the longevity of your oil. Do not smoke the oil before using it, please.
2. Drain the oil and filter it after the first and each subsequent fry. This removes any impurity and unwanted extras which can be acted on by bacteria to cause rancidity and burning the next time you crank the heat.
3. Stand the oil to cool to room temperature and pour in an airtight container to prevent oxidation. Do not place the container in line of direct sunlight but keep in a cool, dark place or in the refrigerator.
4. You might want to label your oil with what you fried in it as food flavors tend to get carried over when reusing the oil. This is to prevent bad flavor overlaps.
Each time you reuse an oil, it gets more and more destabilized until it decomposes. The way the oil starts looking when it starts to decompose is very distinct. If your recycled oil is looking cloudy or has foam formed on top, it is time for it to go. Bad frying oil might be tricky to gage with your eyes, but thanks to the nose, it can't go unnoticed.
Pay attention to what you eat!