How many times can we reuse used frying oil?

Surely, you’ve wondered whether it’s good to reheat oil, if it’s okay to cook with it again after using it, or if there’s any trick or recommendation for doing so.

Today, we’re going to help you stop overthinking it. We’ll tell you how many times you can reuse frying oil and other relevant details that will surely be as practical as they are enlightening. Your health will thank you, and maybe some stomach pains will disappear.

Save by Reusing Oil, But Safely

Oil and Acrylamide

Before anything, it’s important to note one detail. When cooking with oil, each time it’s heated, a series of toxic compounds are formed, with acrylamide being the most notable. This substance naturally forms in starchy foods when cooked at high temperatures. Acrylamide and its metabolite, glycidamide, are considered toxic substances, so it’s important to avoid them.

Considering that most things we fry are starchy foods, such as potatoes, croquettes, dumplings, and other battered items, acrylamide is always present when frying.

Oil and High Temperatures

But it’s not only important to be cautious with starchy foods and not overconsume them, but also with the amount of fried food you eat. When reaching high temperatures, the oxidation process of fats accelerates, releasing other toxic compounds that are absorbed by any food you’re cooking. As a result, no food escapes those toxins released by the oil when it’s burned. Furthermore, each time you reheat or reuse the oil, those toxic compounds are released more easily, meaning at lower temperatures.

If you want to know whether the oil you’re cooking with is releasing these toxic compounds, you can easily check. The best indicator is the smoke. If smoke is coming out, danger. To prevent this, always fry below a temperature of 175°C and limit oil reuse as much as possible.

How Many Times to Reuse Frying Oil

With all the information above, it won’t be surprising when we tell you that, in the specific case of french fries, the Spanish Agency for Consumer Affairs, Food Safety and Nutrition once recommended to always use fresh oil when frying them.

Since it’s not always possible to do so, and not even many restaurants can afford it, it’s recommended to reuse the oil a maximum of three times and always filter it. It’s also advised to use high-quality oils, as well as those less prone to producing toxic substances.

Sunflower Oil vs Olive Oil

With that said, you’re probably wondering which is the best oil for frying considering all of this. You should remember that as long as you don’t use it more than a couple of times, you won’t have an issue. However, you need to consider various factors, both in terms of the type of oil you use and the food you cook, as well as whether or not it released smoke while cooking.

Oil degradation occurs more easily in sunflower oil than in olive oil, so you’ll need to control the temperature carefully and ensure that it never produces smoke. Additionally, it’s worth noting that refined oils can be reused more safely, as they eliminate some of the fatty acids that cause toxic substances.

Important Factors to Consider

But in addition to the couple of times you can use oil, there are other factors to keep in mind. The first one is what you’ve cooked in it. If you’ve fried high-sugar foods, such as churros or doughnuts, you should not reuse the oil. Think about it — they tend to have a high starch content, which means more acrylamide. Has it ever happened to you that after leaving a churrería (fried dough shop) and having churros with hot chocolate, you start to feel a bothersome stomach ache soon after? The likely culprit is oil that was reused more than it should have been. When this happens, the smell of fried food is unmistakable.

On the other hand, you should never reuse oil that has produced smoke, nor if it has become cloudy or if bubbles have appeared on its surface. If you’ve surpassed this limit, you should dispose of it. Remember in this case to properly recycle the oil.

However, if none of the previous conditions apply, and you want to reuse the oil for cooking another day, you should do so in the following way: first, strain or filter the oil to remove any impurities, and then store it in a dry, dark place.