Rice grades explained: what 5%, 15% and 25% broken actually mean

Every rice export contract is written in grade terms. A buyer asks for Thai white rice 5% broken, or Vietnamese 25% broken, or A1 Super. Prices move sharply between grades, and a mill that cannot hit the grade a buyer specifies cannot sell into that contract at any price.

Despite being the common language of the rice trade, these numbers are widely misread. The most common mistake is assuming that 5% broken rice contains 5% broken grains. It does not necessarily contain any particular amount. It means the broken content will not exceed 5%.

That distinction matters commercially, and everything else about grading follows from understanding it properly.

What a rice grade actually specifies

A grade is a ceiling, not a recipe.

When a contract says 5% broken, it sets a maximum. The consignment may contain 2% broken or 4.8% broken and still meet the grade. What it cannot do is exceed 5%. A cargo that tests at 5.4% broken fails the specification, and the buyer is entitled to reject it or renegotiate the price down to the next grade.

This is why mills that consistently produce well inside the limit have a commercial advantage. Running at 3% broken against a 5% specification gives you margin for the variation that occurs between batches, between paddy lots, and between the sample the surveyor draws and the average of the container.

Mills that run right at the limit fail inspections eventually.

How "broken" is defined

Here is where most confusion starts. A broken grain is not simply a grain that looks damaged. It is defined by length, measured against the average length of a whole kernel of that variety.

The categories used across most Asian export standards work like this:

Thai standards express the same idea differently, dividing the notional grain into ten parts. Head rice measures more than 8 parts. Broken sits between 5 and 8 parts. The principle is identical: a fragment counts as head rice if it retains most of its length, and drops into a broken category as it gets shorter.

The practical consequence is that a grain can be visibly cracked and still count as head rice, provided it has not actually separated. And a grain that snaps cleanly into two roughly equal halves produces two pieces that both fall below the three-quarter threshold, turning one head rice grain into two brokens.

The rest of the specification

Broken percentage gets the headline, but it is one line on a spec sheet. A full grade specification typically also sets limits on the following.

Moisture content. Usually a maximum of 14% to 14.5%. Rice above this range will not store safely for the length of a sea voyage, and buyers reject on moisture routinely.

Chalky kernels. Grains where half or more of the surface is opaque white rather than translucent. Chalk is a field and drying issue rather than a milling one, but it is visible in the finished product and limits are usually 3% to 6% depending on grade.

Damaged kernels. Grains discoloured or degraded by heat, water, insects or fungi. Tolerances are tight, often under 2%.

Yellow kernels. Grains that have turned yellow or yellow-brown, usually from heat during storage or delayed drying. Limits are commonly well under 2%.

Red kernels and undermilled kernels. Grains retaining red pericarp or bran that should have been removed during whitening. This one is directly a milling outcome.

Paddy grains. Unhusked grains that made it through the line. Premium grades allow as few as 5 to 7 grains per kilogram. This is a direct measure of how well the husker and paddy separator are working.

Foreign matter. Dust, husk, straw, stones, seeds, insect fragments. Should be near zero, and is a direct measure of pre-cleaning and destoning.

Milling degree. Described as well milled or extra well milled. This is a whitening specification, and it interacts with everything else, because pushing harder for whiteness increases breakage.

A mill can hit its broken target and still fail a contract on any one of these.

The standard grades, in order

Grade naming varies slightly by origin, but the structure below is broadly consistent across Thai, Vietnamese, Indian and Pakistani white rice.

100% grade

The premium tier, subdivided into Grade A, B and C. Despite the name, this does not mean zero broken content. Thai 100% Grade A permits up to 4% broken in the 5 to 8 part range, with the remainder head rice, and requires a minimum whole kernel content. Grades A, B and C separate on chalky, yellow and damaged tolerances rather than on broken content.

Buyers: premium retail, specialty importers, high-end food service.

5% broken

The workhorse premium export grade. Maximum 5% broken, moisture typically 14% to 14.5%, chalky around 4%, damaged around 2%, yellow around 1.5%. This is what most quality-conscious import markets specify for supermarket rice.

Buyers: supermarket retail, branded packers, institutional contracts.

10% and 15% broken

The mid-market grades. Tolerances on chalky, damaged and yellow kernels widen alongside the broken limit. These grades supply wholesale trade and large-volume buyers who need consistent, presentable rice without paying the premium tier price.

Buyers: wholesale distribution, food service, government tenders.

25% broken

The high-volume value grade, and the largest segment of the global rice trade by tonnage. Maximum 25% broken, with correspondingly wider allowances on other defects.

This grade dominates in price-sensitive markets across West Africa, parts of Southeast Asia and the Middle East. It is not a failure grade. It is a deliberately specified product with a very large market.

Buyers: large-volume importers, price-sensitive retail, food aid and institutional supply.

A1 Super and A1 Extra Super

Broken rice grades in their own right, sold as broken rice rather than as white rice that happens to contain brokens. Specified by fragment size rather than by a broken ceiling.

Buyers: brewing, starch and flour processing, pet food, and household consumers in markets where broken rice is preferred.

That last point deserves emphasis. In Senegal, broken rice is not a lower-quality substitute. Traditional dishes including thiéboudienne are made with 25% and 50% broken grades by preference, and Senegal is one of the world's largest importers of broken rice. A mill supplying that market grades its broken output as product. See the Senegal rice industry analysis for how that shapes equipment specification.

What determines the grade your mill can produce

Grade is not decided at the grader. By the time rice reaches the grading stage, the broken content already exists and the grader can only sort what it is given. Grade is determined across the whole line, and in the field before that.

Before the mill: paddy moisture

Paddy that is too dry cracks during husking. Paddy that is too wet deforms under whitening pressure and mills unevenly. Both raise breakage before any machine is adjusted.

Target moisture at milling is generally 13% to 14%. Getting there depends on controlled drying rather than field drying, and it is the single most under-managed variable in most mills. See paddy drying before milling.

Husking: roll gap and roll condition

The rubber roll husker removes husk through differential roll speed and controlled pressure. Set the gap too tight and grains crack as they pass. Let the rolls wear unevenly and pressure becomes inconsistent across the width of the feed.

Worn rubber rolls are the most common single cause of avoidable breakage in a commercial mill, and the cheapest to fix.

Separation: keeping paddy out of the whitener

If unhusked paddy reaches the whitening stage, it is harder than the brown rice around it and it breaks the grains it contacts. An effective paddy separator protects head rice yield and also controls the paddy-grains-per-kilogram line on the spec sheet.

Whitening: the main breakage trade-off

Whitening removes bran by abrasion or friction, and it is where the direct conflict lives. More whitening gives better colour and a higher milling degree. More whitening also breaks more grains.

Multi-pass whitening exists to resolve this. Removing bran in two or three gentler stages produces the same milling degree with markedly less breakage than forcing it through one aggressive pass. See whitening vs polishing.

Grading: sorting, not fixing

The grader separates head rice from broken by length, usually through indented cylinders or a plansifter, and it is what allows a mill to produce defined grades rather than one undifferentiated output.

A grader cannot lower your broken percentage. What it can do is separate your output into a 5% stream and a broken stream, both saleable, instead of one 12% broken stream that only reaches mid-grade pricing. That separation is often where the money is.

Colour sorting: the defect lines

A colour sorter handles yellow, damaged, red and discoloured kernels along with foreign matter that survived pre-cleaning. For premium export grades it is effectively mandatory, because those defect tolerances are too tight to hit reliably by mechanical separation alone.

Moving up a grade

Mills producing 15% or 25% broken output and wanting to reach the 5% tier usually find the constraint in one of four places.

Rubber roll condition and setting. Check this first. It is the cheapest correction available and frequently the largest single gain.

Single-pass whitening. If bran removal happens in one aggressive stage, breakage is structurally high and no downstream adjustment will fix it. Adding a second whitening pass addresses the cause.

No grader, or an undersized one. Without length grading you cannot produce a defined premium grade at all, regardless of how low your breakage is.

Paddy moisture control. If incoming paddy varies between 11% and 17% moisture, output will vary no matter how well the machines are set.

For diagnosing specific symptoms, see common rice milling problems and how to measure and improve milling recovery.

Grade and price

The commercial logic is simple enough to state and easy to underestimate.

Moving from 25% broken to 5% broken raises the price per ton meaningfully. It also raises the value of the broken fraction, because properly graded A1 Super sells better than mixed brokens. A mill that upgrades its line captures both.

Against that, higher grades cost more to produce. Multi-pass whitening uses more power. Colour sorters carry capital cost and require maintenance. Tighter grading produces a smaller head rice stream and a larger broken stream, which only pays if the broken stream is sold properly rather than discounted.

Whether the upgrade is worth it depends on the price spread in your market and whether your buyers will actually pay for the higher grade. In Senegal, they may not, because the market wants broken rice. In Nairobi or Lagos, they will.

Contact Starlight for grading and milling equipment

Starlight supplies the equipment that determines grade: rubber roll huskers, paddy separators, whiteners, polishers and length graders, in configurations from cooperative scale to full commercial production lines.

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Explore our equipment range:

• Grading & Sizing
• Whitening (Emery & Iron Roller)
• Husking & Paddy–Brown Separation
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For terminology used across rice processing, see the Rice Milling Industry Glossary.

Frequently asked questions

What does 5% broken rice mean? It means the consignment contains no more than 5% broken kernels by weight. The remaining 95% or more is head rice, defined as grains at least three-quarters of the average whole kernel length. The figure is a maximum rather than a target, so a cargo testing at 3% broken still meets a 5% specification.

What is the difference between 5% and 25% broken rice? The broken content ceiling, and the tolerances that move with it. 25% broken rice permits up to a quarter of the consignment to be broken kernels, and generally allows wider limits on chalky, damaged and yellow kernels as well. 5% is a premium retail grade; 25% is a high-volume value grade that dominates price-sensitive markets, particularly across West Africa.

Is 25% broken rice low quality? Not in the sense of being defective. It is a deliberately specified grade with a very large global market, and in some countries it is the preferred product rather than a compromise. Senegalese cooking traditionally uses 25% and 50% broken rice by choice. The grade describes composition, not defect.

What is head rice? Head rice is the whole and near-whole fraction of milled rice, defined as kernels at least three-quarters of the average length of an unbroken grain. Head rice yield, expressed as head rice as a percentage of paddy input, is the primary quality measure of a milling operation.

How is broken rice percentage measured? A representative sample is drawn from the consignment, then separated by length using calibrated sieves or an indented cylinder, and the fractions are weighed. Because results depend on sampling, independent surveyors are normally appointed for export contracts and their certificate governs acceptance.

What causes high broken rice percentage in a mill? The most common causes are worn or badly set rubber husker rolls, single-pass whitening at excessive pressure, paddy milled at the wrong moisture content, and unhusked paddy reaching the whitener because of poor separation. Rubber roll condition is worth checking first, since it is the cheapest to correct and often the largest contributor.

Do I need a colour sorter to produce export grade rice? For premium grades, in practice yes. Tolerances on yellow, damaged and discoloured kernels in 5% and 100% grades are tight enough that mechanical separation alone rarely achieves them consistently. For 25% broken supplying domestic or regional markets, a colour sorter is often not required.

What moisture content should milled rice be? Export specifications typically cap moisture at 14% to 14.5%. Paddy is usually milled at 13% to 14% moisture. Higher moisture risks spoilage during a sea voyage and is a routine cause of rejection at destination.

Grade tolerances vary by origin, variety and individual contract. The figures here reflect common Asian export standards and should be confirmed against the specification in any given sale contract. Starlight Machinery is a rice processing machinery manufacturer based in Danyang, Jiangsu, China, supplying combined rice mills, production lines, and individual processing machines to commercial operators, cooperatives and distributors worldwide.