Iodine Value Chart of Oils

Iodine Value Chart of Oils — reference table

How to read this table

The iodine value is a single number that captures an oil's degree of unsaturation — how many reactive double bonds its fatty acids carry — measured as the grams of iodine that add across those bonds per 100 g of oil. The ranges above are indicative: a real oil's value depends on its variety, growing conditions and origin, and the authoritative acceptance ranges for a named, graded oil are set by product standards such as Codex, not by a single remembered figure. Read the table as a map of where each oil sits and how oils compare, rather than as a specification. The oils are ordered low to high, so the table doubles as a ranking from the most saturated and stable oils at the top to the most unsaturated and reactive at the bottom — the single most useful thing the number tells you.

From saturated to unsaturated: the pattern

The clearest pattern in the table is the progression from saturated to unsaturated oils. At the top, the lauric oils — coconut and palm kernel — have the lowest iodine values (single digits to low tens) because their fatty acids are largely saturated, with few double bonds. Palm and the tropical fats sit a little higher. The monounsaturated oils — olive, high-oleic sunflower — occupy the middle, carrying mostly one double bond per fatty acid. Then come the polyunsaturated seed oils — soybean, standard sunflower, safflower, walnut — with progressively more double bonds and higher values. At the very bottom, linseed stands apart as a drying oil. So the iodine value effectively sorts oils by fatty-acid type, which is why it is such a compact and informative index.

What a high or low value tells you

Where an oil falls has direct practical meaning, as explained on the iodine value page. A low IV (top of the table) means a saturated, harder, more stable oil that resists oxidation and tolerates heat — coconut and palm being the obvious examples, solid or semi-solid at room temperature. A high IV (bottom) means a highly unsaturated, liquid, oxidation-prone oil that goes rancid faster and is better kept cool and used sooner (see storing edible oil). At the extreme, very high IV oils are drying oils that harden into a film in air. So a glance at the value predicts an oil's texture, stability, shelf life and even whether it belongs in the kitchen or the paint shop — all from the level of unsaturation the number reflects.

Notable oils in the table

A few entries are worth singling out. Coconut and palm kernel anchor the low end as the classic saturated lauric oils. Linseed (flax) anchors the high end at IV ~170–204 — so unsaturated that it polymerises in air, which is exactly why it is a traditional paint and wood-finish oil rather than a stable cooking oil. Castor is the odd one out: its iodine value is moderate, but its fatty acid (ricinoleic) carries an unusual hydroxyl group, so IV alone does not capture what makes castor distinctive. And sunflower and safflower illustrate the biggest caveat: their standard (linoleic) forms are high-IV and oxidation-prone, but the high-oleic versions bred for stability have a much lower IV, close to olive — so the crop name alone is not enough, the type matters.

Using iodine value for identity and adulteration

Because each oil has a characteristic band, the iodine value is a classic tool for identity and authenticity. If a sample sold as one oil returns a value outside that oil's expected range, it suggests blending, substitution or mislabelling — for example, cutting a premium oil with a cheaper, more unsaturated one would pull the measured IV upward, while adding a saturated oil would pull it down. The table's ranges are what such a check is read against, though the authoritative bands for regulatory purposes are in the Codex and national standards. On its own IV is one line of evidence; combined with saponification value and the full fatty-acid profile it forms part of an oil's chemical fingerprint, which is why authenticity testing rarely relies on any single number.

Iodine value, oxidation and shelf life

One reason this chart is worth keeping to hand is that it predicts how well an oil keeps. Every double bond is a site where oxygen can attack, so an oil's position on the iodine scale maps closely onto its oxidative stability: the low-IV oils at the top (coconut, palm) resist rancidity and tolerate repeated heating, while the high-IV oils at the bottom (linseed, safflower, walnut, standard sunflower) oxidise quickly and develop off flavours sooner. This is the practical logic behind storage advice — the higher an oil's iodine value, the more it benefits from being kept cool, dark and airtight and used within a shorter window, as set out in how to store edible oil. It is also the logic behind the high-oleic breeding of sunflower and safflower: deliberately lowering the iodine value (fewer polyunsaturated bonds, more monounsaturated) produces a more heat-stable frying oil without fully saturating it. So the number is not an abstract index but a working predictor of shelf life and frying suitability.

Iodine value beyond food: drying oils

The high end of this chart defines a whole category of industrial oils. Oils with a very high iodine value — above the food range — are "drying oils": their abundant double bonds let them react with oxygen in air and polymerise into a tough solid film, the property behind oil paints, varnishes, wood finishes and linoleum. Linseed (flax) and tung oil are the classic examples, sitting at the very bottom of the table. Oils in the middle of the range are semi-drying, and the low-IV oils are non-drying. So the same figure that warns a food chemist an oil is perishable tells a coatings chemist it will cure into a film — two applications of the one underlying fact, that unsaturation makes an oil chemically reactive toward oxygen. It is a neat illustration of why a single, simple parameter has stayed so useful across such different industries.

Iodine value and the saponification value

The natural companion to this chart is the saponification value chart. The two parameters describe different things: iodine value reports unsaturation (double bonds), while saponification value reports average fatty-acid chain length (molecular weight). Read together, they sketch both the shape and the size of an oil's fatty acids, which is why they are the classic pair used to characterise and identify an oil. Neither changes much as an oil ages — unlike acid value and peroxide value, which climb with hydrolysis and oxidation — so IV and SV answer what an oil is, while the freshness parameters answer what condition it is in. For the full set of quality parameters and how they are used together, see the quality-testing guide.

Related pages

Iodine value (definition)Saponification value chartQuality testing guideCodex oil standardsOilseeds

FAQ