Expeller Pressed vs Cold Pressed Oils: Everything You Need to Know

The methods of essential oil extraction have evolved, progressing from arduous, time-consuming techniques to automated, efficient processes. The earliest essential oils were prepared by placing parts of plants in odorless fatty oils. Some essential oils were derived by a technique called expression, where plant parts such as peels were squeezed to obtain the oil. 

Among modern techniques of essential oil extraction are chemical distillation, cold pressing, and expeller pressing. When looking through aisles of essential oils, it might be confusing to decide which extraction method suits your needs. You might notice that the extraction method affects the price, color, texture, and quality of essential oils. 

For cosmeceutical purposes, mechanical methods of essential oil extraction, such as cold pressing and expeller pressing, are better as the extraction process requires less refinement. While all mechanical expression methods have their merits, cold pressing preserves the original aromatic and therapeutic profile of the oil better.

This article will guide you through the evolution of essential oil extraction methods and the difference between cold pressed and expeller pressed essential oils so you can confidently shop for the essential oil you need.

Overview of Essential Oil Extraction Methods 

Spurred by the growing demand for natural medicine and the onset of the Industrial Revolution, essential oils began being mass-produced in the late 19th century. Since then, several methods have been developed for the extraction of essential oils, the most popular being steam distillation. This is a standard method in the aromatherapy industry due to its efficiency, cost-effectiveness, and preservation of aromatic compounds. 

Other extraction methods include chemical extraction techniques such as solvent extraction and carbon dioxide extraction. In solvent extraction, plant material is dissolved in a chemical solvent such as ethanol or hexane. The solvent absorbs oil-soluble compounds, forming a solution that is filtered to separate the essential oil. This is an effective technique for extracting essential oil from plants with low oil content but it may leave behind solvent residue. 

On the other hand, carbon dioxide extraction, also known as supercritical fluid extraction, is a newer method that yields high-quality essential oils without heat treatment. This is used with selective plants as it is expensive and may extract only certain compounds. 

Many plants necessitate the use of physical extraction techniques to derive their aromatic compounds. Citrus peel essential oils are commonly extracted via expression, a technique where the peels are mechanically pressed until they express the oil. Cold pressing and expeller pressing are other physical extraction techniques. While these techniques are closely linked, there are important differences between the two that can affect oil characteristics. 

Most carrier oils derived from the nuts and seeds are either cold pressed or expeller pressed. This is because both of these methods use a mechanical screw to obtain the oil, ensuring a consistent and controlled extraction. 

Key Differences Between Cold and Expeller Pressed Oils

Expeller pressing and cold pressing are both mechanical extraction methods that yield oils with subtle differences. All oils that are labeled cold pressed fall under the category of expeller pressed oils. However, it is important to note that the converse is not always true–expeller pressed oils do not universally qualify as cold pressed oils. As a consequence, cold pressed oils can be categorized as a specialized subset of expeller pressed oils. 

The following sections expand on both extraction processes and the way they affect the characteristics of the final product. 

Extraction Process

Both cold pressed and expeller pressed oils begin their journey at the same place: a mechanical screw press, also known as an expeller machine. Expeller press machines feature a giant screw, which is the primary component responsible for oil extraction. The process begins with the cleaning and preparation of raw plant materials such as seeds, nuts, and fruits. Once prepped, the material is fed into the expeller press. 

As the screw rotates, it crushes the plant material and squeezes oil by exerting continuous mechanical pressure. The oil seeps through a filter in the expeller machine and collects in trays, ready to be filtered and used commercially. 

Manufacturers can choose to adjust the screw rotation speed and the temperature that the plant material is exposed to. In cold pressing, the goal is to use lower rotation speeds to reduce friction and heat generation. Hence, cold pressing involves a more controlled approach to ensure that oil characteristics are preserved. 

Temperature Variation

Perhaps the most important point of distinction between cold pressing and expeller pressing is the temperature during the extraction process. Although both methods do not introduce heat into the production, regular expeller pressing generates heat from friction. As the screw spins and presses the plant material against the barrel, the temperature within the barrel rises. During regular expeller pressing, temperatures can reach 140 degrees Fahrenheit. 

Cold pressing is a controlled form of expeller pressing where the temperature is moderated to stay within 100 degrees Fahrenheit. Cold press operators control temperature through several techniques, including reducing screw rotation speed, taking frequent breaks while pressing, and using fans to cool the chamber. 

Therapeutic Effect

Since the extraction process for expeller and cold pressed oil involved little to no heat, the therapeutic properties of the plant compounds remain preserved. When compared, however, expeller pressed oils may have slightly reduced efficacy as temperatures can go up to 200 degrees Fahrenheit during extraction.

While the difference in therapeutic effect is mostly negligible, it may be pronounced if the plant consists of heat-sensitive chemical constituents. In the case of coconut oil, it is better to use cold pressed coconut oil as it may lose antioxidant properties if exposed to heat. Polyphenol compounds in coconut oil are not thermally stable and may lose efficacy if extracted through methods that introduce heat. 

Aroma and Flavor Profile

Generally, expeller pressing and cold pressing do not produce a noticeable difference in aroma and flavor. At the utmost, the sensitivity of source material and extraction method might introduce subtle variations in aroma and flavor discernible only to trained senses.

Cold pressing completely preserves volatile compounds and hence cold pressed oils may smell ‘fresher’ and more vibrant. On the other hand expeller processing may slightly deepen the scent and flavor, altering the original profile. For cosmetic and personal care use, there is virtually no difference between expeller and cold pressed oils when it comes to flavor and aroma.

Chemical Composition 

This is an important factor especially when considering oils for beauty and therapeutic uses. The chemical profile of an oil has the potential to affect its health benefits. While both expeller pressing and cold pressing aim to maintain the original characteristics of the oils, the two processes have distinct effects on bioactive compounds. 

Expeller pressing introduces moderate heat into the extraction process, potentially affecting the oxidation of fatty acids and diminishing the qualities of thermally unstable compounds. Cold pressing takes away the risk of oxidative reaction as it minimizes heat exposure in the extraction chamber.

Yield and Efficiency

Altering any environmental and operational factor in the production process can affect oil yield. Modern expeller press machines allow for several settings and modes depending on the type of screw used, screw diameter, and rotation speed. The quality of seeds and their moisture content also influence the amount of oil produced.

Expeller pressing extracts a comparatively higher amount of oil in comparison with cold pressing. This is because the process uses higher screw rotation speeds, also generating more friction and heat. This significantly increases oil yield, making expeller pressing more efficient and economical in comparison with cold pressing. 

Answering Essential Queries Regarding Expeller and Cold Pressing

Navigating mechanically pressed oils might be confusing as there is a lot of contradicting literature on the web. The following sections aim to answer common queries regarding cold pressed and expeller pressed oils. 

Are Expeller Pressed and Cold Pressed Oils Pure and Natural?

It can be tough to discern between marketing terms and regulated labels in the world of essential oils. You will find terms such as “therapeutic grade”, “100 percent pure”, and “100 percent natural” on essential oil labels. Since these terms are not regulated, they don't actually convey anything meaningful about the quality and purity of oils. 

A good indicator of the quality and purity of oils is their chemical composition. Oils that are extracted through chemical methods are more susceptible to losing their purity as a result of additives and chemical residue. Cold pressed oils and expeller pressed oils are both pure as they contain only the oil extracted from the source material. 

Does the Extraction Method Affect Shelf Life?

The shelf life and stability of natural oils are affected by several factors such as extraction method, plant characteristics, and exposure to oxidizing agents. The extraction method significantly affects shelf life as it controls the moisture content and chemical composition of oils. 

Cold pressed oils have a short shelf life as their extraction process does not involve a lot of refinement. This means that destabilizing compounds such as free fatty acids are not removed from the oil, causing it to oxidize faster.

In comparison, expeller pressed oils may have a slightly longer shelf life as their extraction process involves more refinement, sometimes including the addition of preservatives. This slows the deoxidization of chemical constituents, improving the stability of the oil. Always take care to verify the shelf life of your pressed oil from the manufacturer to avoid using oxidized oil. 

To extend the shelf life of your cold pressed and expeller pressed oils, ensure that you place them in cool, dark areas such as in a cabinet. Also, make sure that the storage container or bottle is sealed properly so that the oil is not exposed to the air. 

What Causes Color Variations Between Cold Pressed Oil Batches?

If you frequently buy cold pressed oils, you may notice that the color of your oil varies between batches. This raises a concern for many that their oil might be adulterated. The good news is that pure and natural cold pressed oils tend to vary in color due to many factors associated with the production process and source plants.

Sometimes, weather changes may cause changes in plant pigments, and affect the color of seeds and flesh. Another factor that can cause irregularity in appearance is the maturity of the raw plant material as seeds and nuts change color between stages of ripeness.

Does the Lack of Heat Treatment in Cold Pressed Oils Pose a Hygiene Risk?

Fortunately, despite the minimal, low-heat extraction process, cold pressed oils are safe to use. When purchasing cold pressed oils, ensure that you source from a reputed and trusted supplier, like Wholesale Botanics, to avoid the risk of contaminants. 

You can validate the reliability of the seller by examining product labels for transparent descriptions of the oil’s sourcing, country of origin, and chemical composition. Environmental friendly and sustainable sources are also trustworthy as they employ standardized procedures and consistent protocols.

What Does Hexane-Free Oil Mean?

Many companies label their oils with claims such as “hexane-free.” This indicates that the oil has been extracted without using the chemical solvent hexane. It does not necessarily mean that the oil is pressed, as oils can be chemically processed with a hexane substitute. 

Unless an oil bottle is labeled ‘cold pressed’ or ‘expeller pressed’, terms such as ‘hexane free’ do not ascertain that it is mechanically pressed. Hence, when looking to purchase pressed oils, ensure that the labels explicitly indicate that it is cold or expeller pressed. 

Can Cold Pressed Oils Be Used for Cooking?

Cold pressed oils sold for cosmeceutical purposes are not suitable to be used in cooking. While they are pure and organic, they are ‘cosmetic grade’ and do not undergo the same level of refinement as edible oils. Food-grade oils are prepared and refined differently to ensure that there are absolutely no contaminants and minor compounds that might have undesirable effects when consumed. 

Hence, never use cold pressed essential oils or carrier oils for cooking unless the label specifically states that it is edible or food grade. 

Best Cold Pressed Oils to Use

While all cold pressed oils have healthful properties and therapeutic effects, some deserve special praise. The following sections curate the most therapeutically efficient cold pressed oils that will serve you multiple purposes!

Coconut Oil

The skincare community has honored coconut oil with many titles, including ‘liquid gold’ and ‘beauty balm’. A glance at the chemical profile of this popular carrier oil explains the hype: it consists mostly of natural saturated fats, vitamin E, and vitamin K. 

Coconut oil has many benefits for skin health, such as improving skin barrier function and promoting a radiant appearance. Due to its fat content, coconut oil improves skin elasticity and suppleness by protecting the skin barrier. It can also be used on its own or mixed with olive oil as a hair mask to nourish hair follicles. 

When using coconut oil in facial treatments, always patch test first to avoid breakouts and inflammation. 

Argan Oil 

Argan oil has a diverse chemical composition with constituents such as fatty acids, polyphenols, sterols, and vitamin E. It is derived from the kernels of the argan tree native to Morocco. Due to its lightweight texture, argan oil can be used by nearly all skin types to provide hydration and moisture. It also contains squalane, a compound that improves skin elasticity by moderating collagen production.

This gold elixir also finds many uses in hair care due to its hair conditioning and frizz-control properties. The high fatty acid content makes it a useful treatment for dry hair. You can also massage it into your nail bed for stronger, shinier nails. 

Sweet Orange Essential Oil

Sweet orange essential oil is derived from the peel of Citrus sinensis, a widely cultivated species of orange tree. It has a sweet, citrusy scent that is great for brightening up the environment. It consists of notable chemical constituents such as limonene, myrcene, and alpha-pinene. 

The essential oil can be used for many purposes, such as boosting energy levels and reducing stress through aromatherapy. It can also be used in skincare routines to brighten complexion, manage acne, and reduce signs of aging. 

Its strong, bright scent can be utilized as a natural fragrance in home care. Add it to a DIY linen spray or simply diffuse it in your room to neutralize any odors and add a pleasant scent.

Cold Pressed vs Expeller Pressed Oils: Key Takeaways

Understanding the extraction methods of cold pressed and expeller pressed oils can help you make an informed decision when you go shopping. To ensure you make the right purchase, here are a few additional points to consider when choosing a seller:

Research the seller’s sourcing methods to ensure transparency and ethical sourcing methods

• Choose oils packaged in dark, opaque glass bottles and avoid clear packaging
• Check labels and website descriptions for quality certifications and reports
• Verify oil purity by checking the ingredients list for any additives
• Steer clear of sellers that advertise extravagant health claims and/or solicit medical advice

If you keep these tips in mind, you can feel confident in your purchase, no matter which extraction method you choose.