What is head rice?
Head rice is the whole-kernel fraction, including sufficiently long kernels under the grading definition being used. Report that definition and the mass basis whenever you quote a head-rice result.
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Why the definition matters
A quality figure is only comparable when the sampling and grading rules match. Record the reference kernel length and the cut-off used by your grading method instead of treating every unbroken-looking grain as equivalent.
Two different percentages
The proportion of head rice within milled rice uses a different denominator: head rice mass divided by total milled rice mass. Label the result so a buyer or operator can tell which measurement you mean.
Worked arithmetic example
For an illustrative batch with 1,000 kg paddy input, 550 kg head rice and 100 kg broken rice, head rice recovery is 55%. Head rice as a share of the 650 kg milled rice is about 84.6%. These are arithmetic examples, not expected performance values.
Sampling checklist
- Identify the input batch and cleaned-input basis.
- Use representative samples and one grading method.
- Weigh the separated fractions with suitable equipment.
- Keep moisture and test-condition notes with the result.
Investigating a lower result
Compare the incoming grain and successive process samples. A final low head-rice result does not show whether damage occurred before arrival, during husking or during whitening.
Related measures
Total milling recovery includes head and broken rice together. A change in their relative amounts can be hidden if only total recovery is recorded.
Check your batch with the milling yield calculator.
Sources & further reading
References support general principles. Machine-specific settings require the matching manufacturer manual.
- Milling yields ↗IRRI Rice Knowledge Bank · Recovery terminology and comparison of milling systems.