Surely on more than one occasion you have wondered saving the used oil and reuse it for another meal. It is an easy question, but it has a complex answer. Before answering you must know the properties of the oil and what happens when it is subjected to many factors. It doesn’t only depend on the number of times that we can reuse the frying oil, because there are many variables that affect directly on it such as the food, the temperature that the oil can reach, the type of oil with which we are cooking or even the pan we will use.
 

The signal to know if the oil has become toxic

 
The “smoke point” is when you see smoke on the surface of the oil while you are cooking. It is more important than it may seem, because it means that the oil is already very hot, but also it is a sign that the oil begins to lose properties and even become toxic.
 
When this happens, the main problem is the formation of fatty polymers, which carries a high long-term risk of cardiovascular accidents. But a used oil is not only dangerous for health, it is also capable of spoiling food (which absorbs the oil) and it finally has strange colors and flavors.
 
But, as if all that wasn’t enough, reused oil has an additional danger when something fried has little protein and a wide base of sugars. That is why it is so important to fry foods with low sugar levels. And if you do, and you are one of those who like to fry churros on winter and cold Sundays, always try to use clean oil.
 

How to know if the oil can no longer be used

 
The grounds that form at the bottom of the fryer or pan are one of the signs that indicate that we must change the oil. But if we have been filtering and cleaning it, you won’t realize if it is time to change it. A key to know that you must change the oil is the appearance of bubbles while you are cooking.
 

So,how do we fry? What is the recommended oil for frying?

 
Obviously, it will always be better and healthier to fry with clean oil. However, if we do not usually fry foods high in sugars, there is a certain margin for reuse, which is quite wide depending on the circumstances. For example, the type of oil we use for frying, the frying temperature or the utensils and pans we use for cooking.
 
It is convenient to keep in mind that the “smoke point” will be lower if the oil is cleaner. Studies indicate that the most recommended oil for frying is olive oil. Since sunflower oil generates much more toxic aldehydes (and in less time) than olive oil. Now, what really determines whether frying oil can be reused is the temperature. If we have exceeded the “smoke point” in the first use, no matter what type of oil was used, it is not recommended to reuse it for another occasion.
 
On the other hand, another notable factor is that the fry food. It always needs to be very dry before putting it on the hot oil, therefore, it is advisable to leave the food at room temperature for a long time before introducing it in the oil, since the water favors the decomposition of the oil. After cooking, always filter the oil and store it in a jar without humidity and where the light does not penetrate.
 

What to do with the used oil we have at home

 
Think twice what to do with the oil you just used for cooking, because throwing it in the sink is not a good option. According to studies, two thirds of the oil used in Spain ends up in the sewers (about 120,000,000 liters), a very ecological gesture that causes serious problems: stuck pipes, more work in treatment plants, pollution (only one liter of oil can contaminate 100,000 liters of water), and so on. The best way to contribute and improve in this aspect is to have an empty water bottle at home and refill it with the reused oil. After this, leave them in specific containers or in clean spots.
 

Recommendation. Our 3 advices

 
1. If you are a person who likes taking care of yourself and the planet, our recommendation is to do not use more than three times the same oil, since the oil disarms its caloric potential in the third frying.
 
2. Never ever throw oil in the sink, so you won’t help the planet or your city to be clean. It is better to go once every three months to a clean point and deposit the oil there.
 
3. Having an oil container for each thing is a good technique to save and keep the oil as healthy as possible. So, when you cook french fries have a jar for this oil, another for fish and another for coated food.
 

Read more

 
WHAT IS PFOA? WHAT IS PTFE? ARE THEM TOXIC? SOLVE YOUR DOUBTS.
 
HOW TO DISTINGUISH BETWEEN A GOOD NON-STICK FRYING PAN AND A BAD ONE AT A GLANCE.
 
THE 5 BASIC RULES TO USE, CARE AND CLEAN NON-STICK POTS AND PANS WITHOUT READING THE INSTRUCTION MANUAL.