Refiners judge crude palm oil on three numbers. Free fatty acids (FFA) set the refining loss. Moisture and impurities (M&I) affect storage stability and how much of the weight you pay for is oil. The deterioration of bleachability index (DOBI) shows how easily the oil will bleach to a good colour. A typical contract allows FFA up to 5%, M&I up to 0.25% to 0.5% and sets a DOBI minimum, often around 2.3.
This guide explains each parameter and how it shows up in your refinery costs. For our supply terms, see crude palm oil from Liberia.
Typical contract limits
| Parameter | Common limit | Effect if out of specification |
|---|---|---|
| FFA (as palmitic) | 5.0% max | Higher refining loss, more fatty acid distillate |
| Moisture and impurities | 0.25% to 0.5% max | Hydrolysis in storage, paying for water and dirt |
| DOBI | 2.3 min (often higher) | More bleaching earth, poorer colour, lower yield |
| Iodine value | 50 to 55 | Outside range suggests mixing with other oils |
| Peroxide value | Agreed per contract | Oxidation, flavour stability |
Standard contract forms set some of these by default. Check whether your contract follows FOSFA, PORAM or bespoke terms, and whether the price adjusts for FFA above or below a base level.
Free fatty acids (FFA)
FFA is the share of fatty acids that have split off from the triglycerides, expressed as palmitic acid. In the fruit, an enzyme starts breaking down the oil as soon as the fruit is bruised or cut. FFA therefore rises when fruit is harvested overripe, damaged in handling or left too long before it reaches the mill.
In the refinery, free fatty acids are removed as fatty acid distillate during physical refining. That distillate sells for less than refined oil, so every point of FFA costs money. FFA can also rise in storage and transit if the oil is wet or kept too warm.
What to look for: a load port FFA well under the limit, and a contract clause that sets out how FFA rises in transit are handled.
Moisture and impurities (M&I)
M&I is reported as one figure but covers two things. Moisture speeds up hydrolysis, which raises FFA in storage. Impurities, such as fibre and sludge from poor clarification, settle in tanks and carry their own weight in the invoice.
A low M&I is a sign of a well-run mill with good clarification and drying. A rising M&I between load port and discharge usually means water got into the cargo, for example through a damaged flexitank or wet tank.
DOBI
DOBI is the ratio of absorbance at 446 nm (carotenes) to absorbance at 269 nm (oxidation products). It tells you how much of the oil's colour will bleach out easily and how far the oil has oxidised.
Industry guides often group DOBI as follows:
| DOBI | Bleachability |
|---|---|
| Above 3.24 | Excellent |
| 2.93 to 3.24 | Good |
| 2.31 to 2.92 | Fair |
| 1.78 to 2.30 | Poor |
| Below 1.78 | Very poor |
Low DOBI comes from delays between harvest and processing, overheating at the mill and long or hot storage. It cannot be fixed later. A refiner pays for low DOBI in extra bleaching earth, longer processing and sometimes off-colour product.
Other parameters refiners ask for
- Iodine value: confirms the oil is palm oil and not blended.
- Peroxide and anisidine value: measures of primary and secondary oxidation.
- Carotene content: relevant if you produce red palm oil or recover carotenes.
- Trace metals: iron and copper speed up oxidation. Ask for results if your process is sensitive.
- Contaminants: EU buyers may test for 3-MCPD and glycidyl ester precursors, mineral oil hydrocarbons and pesticide residues. Agree in advance which tests apply and who pays.
How quality is checked before shipment
An independent surveyor samples the oil from shore tanks before loading and again during loading, then tests it against the contract. Sealed samples are retained. Read inspection and certificates of analysis for how to use those results if a dispute arises.
Liberian CPO in practice
Quality varies between mills and with the season, because fruit supply and mill throughput change through the year. We build parcels to your specification and test them before loading, so you know what you are buying before you pay against documents. Refiners in West Africa and the EU can read more in Liberian palm oil for refiners.