Refined VS Unrefined Oils

Which Is Better For Household Cooking?

With the vast array of cooking oils available on supermarket shelves, it’s not surprising that you feel overwhelmed. Finding the right oils can be tough if you have no idea what to look for. On a very fundamental level, it is crucial to be aware of whether your cooking oils are refined or unrefined. Which one is better? Read on to find out more!

Refined Oils

Refined oils are oils that are processed using high heat and chemicals, such as hexane to extract the maximum amount of oil from the seeds. In the refining process, the oil undergoes degumming, neutralisation, bleaching, deodorisation, in which different chemical solvents are employed. Making oil is such a simple process but why do refined oils still exist? The reasons are:

Some seeds such as rapeseed (canola), soybean, corn, sunflower and safflower cannot yield oil through the natural extraction process. To extract oil from these seeds, chemical refining process is necessary.

The refining process gives a higher oil yield. For instance, 2.5kg of peanuts are needed to make 1 litre peanut oil if cold pressing method is employed. The refining process requires just 2.2kg of peanuts to make 1 litre of oil.

Since refined oil has been decolourised and deodorised, low quality seeds can be used for extraction. On the other hand, unrefined or cold pressed oil has to use only good quality seeds, otherwise the result would be oil  with noticeable inferior quality.

Cons of refined oils: 

  • Refining markedly decreases nutrients such as essential fatty acids, antioxidants and vitamins in the oil, in addition to removing the natural aroma of the oil.

  • Residues of chemicals which could be harmful to health may be left behind in the final product.

Pros of refined oils: 

  • High smoke point (temperature at which the oil starts to smoke) and thus, can be used for high-heat cooking such as deep-fry. The more refined an oil, the higher its smoke point, because refining removes impurities and essential fatty acids that can cause the oil to smoke.

  • More stable and have a longer shelf life than unrefined oils as it is chemically treated. There is nothing to be spoilt since there is no organic life in it.

Unrefined Oils

Unrefined oils refer to oils that are minimally processed using mechanical extraction (pressure) and with minimal or no usage of heat. During the process, no chemical solvents, no high-heat temperatures and no further refining are used to alter the colour and scent of the oil. In most cases, they are also referred to as “cold-pressed”, “virgin” or “extra virgin”. They are either cold-pressed or expeller-pressed from the seed, nut, etc.

unrefined oils - expeller-pressed

Expeller-pressing involves the use of friction and continuous pressure to squeeze oil from seed or nut through a barrel-like cavity. The friction created during the pressing may produce higher temperatures of approximately 49-93°C (120-200°F).

unrefined oils - cold pressing

Cold-pressing is simple and does not require much energy. The temperatures are controlled at 26-32°C (80-90°F) and the oil extracted retains far more antioxidants and nutrients than it would at higher temperatures.

Both cold-pressed and expeller-pressed oils are potentially more beneficial than refined oils, which are bleached and deodorised. If comparing both of them, cold-pressed oils are perhaps better, since they preserve a greater amount of nutrients compared to expeller-pressed oils.

Manufacturing Process of Unrefined Oil

 

Manufacturing Process of Unrefined, Cold Pressed Oil

Pros of unrefined oils:

  • Minimal processing ensures a high quality, nutrient-rich, authentic-to-nature oils which retain their fresh original taste and colour. 

  • No chemicals are used during extraction and thus, safe for long-term consumption.

Cons of unrefined oils: 

  • Most unrefined oils have low smoke points and may not be suitable for high-heat cooking.

  • In general, unrefined oils tend to be less stable and turn rancid more quickly than refined oils, this may affect their shelf life.

unrefined oils - camelina oil

In a nutshell…

Unrefined oils are better for household cooking. They are rich in nutrients, including essential fatty acids, vitamin E, antioxidants and thus, are way healthier than refined oils. Unlike refined oils, they are free of chemicals which are usually added to the oils during the extraction process. They also retain all their natural aroma and flavour and hence, will add more taste to the dishes. Since they have low smoke point, they should ideally be used unheated such as as a salad dressings or in low-heat cooking, such as simmering, steaming or sautéing.