Palm oil is made by harvesting ripe fruit bunches from oil palm trees, then separating the oil from the fruit through a combination of heat, mechanical pressing, and filtering. The process ranges from simple village-level methods requiring little more than a pot and a mortar to massive industrial mills that process hundreds of tons of fruit per day. Here’s how it works at every scale.
Where Palm Oil Comes From
Oil palm trees (native to West Africa, now grown extensively in Southeast Asia) produce large clusters of reddish-orange fruit called fresh fruit bunches, or FFBs. Each bunch can weigh 10 to 25 kilograms and contains hundreds of individual fruits about the size of a small plum. The oil comes from two parts of the fruit: the fleshy outer pulp, which yields palm oil, and the hard inner seed (the kernel), which yields a separate product called palm kernel oil.
The fruit’s fat composition is roughly half saturated and half unsaturated. The dominant saturated fat is palmitic acid, making up about 42% of the total, while oleic acid (a monounsaturated fat also found in olive oil) accounts for another 41%. A smaller fraction, around 11%, is polyunsaturated linoleic acid. This balance of fats gives palm oil its distinctive semi-solid texture at room temperature and makes it incredibly versatile in cooking and food manufacturing.
The Traditional Small-Scale Method
In many parts of West and Central Africa, palm oil is still made by hand using techniques passed down for generations. The steps are straightforward, though labor-intensive.
First, ripe fruit is stripped from the bunch and boiled in water to soften the pulp and loosen the outer skin. The softened fruit is then pounded in a mortar or ground into a thick paste. This paste gets mixed with a small amount of water and heated in a large pot. As the mixture simmers, oil rises to the surface and is periodically skimmed off with a ladle. The skimmed oil is heated again on its own to drive off remaining water, leaving behind a rich, deep-orange oil with a characteristic nutty flavor.
For palm kernel oil (from the inner seed rather than the pulp), the process is slightly different. Dried kernels are fried in old oil or heated until brittle, then pounded or ground into a paste. That paste is mixed with water and heated, and the lighter kernel oil floats to the top for skimming. Palm kernel oil is lighter in color and has a different fat profile than regular palm oil, with a higher proportion of lauric acid.
Industrial Milling: From Fruit to Crude Palm Oil
Commercial palm oil production follows a series of carefully controlled stages. Mills are typically located close to plantations because the fruit begins to degrade within 24 hours of harvest, and delays reduce both oil quality and yield.
Sterilization
Whole fruit bunches are loaded into large pressurized vessels and blasted with steam at around 140°C and 2.5 bar of pressure for 60 to 90 minutes. This high-pressure cooking serves several purposes at once: it deactivates enzymes that would break down the oil into unwanted free fatty acids, loosens individual fruits from the bunch, and softens the pulp for easier processing. Getting the timing right matters. Too short and the fruit won’t separate cleanly; too long and you lose oil to absorption into the empty bunch fibers.
Stripping and Digestion
After sterilization, the bunches enter a rotating drum that shakes and tumbles the individual fruits free from the central stalk. The loose fruits then move into a heated vessel called a digester, where spinning arms mash and break open the fruit at high temperature. This ruptures the oil-bearing cells in the pulp, creating a hot, oily mash ready for pressing.
Pressing
The mashed fruit is fed into a screw press, which squeezes out a mixture of oil, water, and cellular debris. The solid cake left behind contains the palm nuts (kernels), which get sent to a separate cracking and separation line for palm kernel oil production. The liquid that comes out of the press is a murky mixture that needs significant cleaning before it resembles anything you’d recognize as oil.
Clarification
The press liquid is diluted with hot water and fed into clarification tanks, where it separates into layers. Clean oil rises to the top, while water, sediment, and residual solids (called sludge) settle below. The top layer is skimmed off, dried to remove moisture, and filtered. The result is crude palm oil, a deep orange-red liquid rich in carotenoids (the same pigments that make carrots orange). The sludge layer goes through centrifuges and additional processing to recover any remaining oil before being discarded.
Refining Crude Oil Into a Finished Product
Crude palm oil is edible, and in many tropical countries it’s used directly in cooking. But most commercial applications require a more neutral, shelf-stable product. Refining transforms the crude oil into what the industry calls RBD palm oil: refined, bleached, and deodorized. This is the form found in most packaged foods, cosmetics, and industrial products worldwide.
The process has four main stages. Degumming comes first: hot water or a dilute acid is added to the crude oil to pull out gummy phospholipids and other colloidal impurities, which clump together and are removed by centrifuge. Next, deacidification neutralizes free fatty acids using an alkali solution. The fatty acids react with the alkali to form a soapy byproduct that separates from the clean oil.
Decolorization follows. The oil is mixed with an absorbent clay (and sometimes activated carbon) under vacuum while being stirred and heated for about 25 minutes. The clay binds to pigments, residual gums, and trace metals, then gets filtered out. The once-vivid orange oil becomes a pale yellow. Finally, deodorization heats the oil past 100°C in a vacuum tower, where steam strips away volatile compounds responsible for flavor and smell. This last step also raises the oil’s smoke point, making it more suitable for frying and high-heat cooking.
Contaminant Risks During Refining
The deodorization step, which uses the highest temperatures in the entire refining process (typically 220 to 280°C), can trigger the formation of unwanted chemical byproducts. The most scrutinized are a class of compounds called 3-MCPD esters and glycidyl esters, which form when chloride-containing compounds in the oil react with fats at high heat. The presence of acids introduced during earlier degumming and bleaching stages can make this worse. Refiners manage this risk by optimizing temperatures, minimizing acid carryover, and sometimes using modified refining sequences, but it remains an active area of concern for food safety regulators.
Fractionation: Splitting Oil Into Different Products
After refining, palm oil is often separated into two fractions with distinct physical properties. The oil is slowly cooled under controlled conditions, which causes the higher-melting fats to form crystals while the lower-melting fats stay liquid. Filtration then separates the two.
The liquid fraction, called palm olein, stays clear at room temperature and is widely used as cooking oil, especially in tropical countries. The solid fraction, palm stearin, is firmer and higher in saturated fat. It’s used in margarine, shortening, soap, and as a cocoa butter substitute in confectionery. The two fractions crystallize through different mechanisms: stearin forms rounded, three-dimensional crystal structures, while olein tends toward flatter, plate-like crystals. This difference in crystallization behavior is what makes clean separation possible.
Sustainability and Certification
Palm oil production has driven significant tropical deforestation, particularly in Indonesia and Malaysia, which together account for roughly 85% of global supply. The Roundtable on Sustainable Palm Oil (RSPO) sets voluntary standards for growers and supply chains, certifying that oil was produced without clearing primary forest or high-conservation-value land. Their current framework, updated to version 4.2 in 2024, covers large plantations as well as independent smallholders, who produce a substantial share of the world’s palm oil. A separate supply chain standard ensures that oil sold as “sustainable” can be traced back to certified sources.
RSPO certification is the most widely recognized label, but it covers only a fraction of global production. If you’re sourcing palm oil for food production or personal projects, looking for the RSPO trademark on packaging is the most practical way to choose a more responsibly produced option.