Why Is My Rice Mill Producing Too Much Broken Rice?
Excessive broken rice is not always caused by the rice mill itself. Common causes include paddy that is too dry, kernels cracked before milling, excessive whitening pressure, aggressive milling settings, worn machine parts or trying to remove too much bran in a single stage.
On this page
Quick Diagnosis
| Symptom | Check first | Why |
|---|---|---|
| Broken rice suddenly increased | Machine setting or worn part | A sudden change often suggests a machine or adjustment change. |
| Broken rice is consistently high for one batch of paddy | Moisture and grain condition | The problem may already exist in the raw material. |
| Rice becomes very hot during whitening | Milling pressure and feed rate | Excessive mechanical stress may be occurring. |
| Broken rice increased after maintenance | Roll gap, pressure and replaced parts | A new adjustment may be too aggressive. |
Cause 1 — Paddy Is Too Dry
Dry kernels are more brittle and can break more easily under mechanical stress.
Measure moisture with a moisture meter rather than judging grain only by appearance.
Around 14% moisture is often used as a practical milling reference, although the optimum condition depends on rice variety and processing history.
Cause 2 — The Grain Was Already Cracked
Drying and handling can create internal fissures before the rice reaches the mill.
The machine may simply expose a problem that already exists.
Compare:
- incoming paddy
- brown rice after husking
- rice after whitening
This helps identify the stage where breakage increases.
Cause 3 — Whitening Pressure Is Too High
Excessive milling pressure can increase mechanical stress.
If breakage rises together with:
- higher grain temperature
- stronger motor load
- aggressive whitening
reduce milling severity and check machine settings.
Cause 4 — Too Much Milling in One Stage
A multi-stage process can distribute bran removal rather than forcing one machine to do all the work.
If the target finish requires heavy whitening, consider whether the process itself is too aggressive.
Cause 5 — Worn or Incorrect Machine Parts
Inspect:
- whitening screen
- milling roller
- bearings
- rubber rolls
- feeding components
A worn component can change grain movement and machine behavior.
A Better Diagnostic Method
Do not change five machine settings at once.
Instead:
- Measure incoming paddy moisture.
- Inspect incoming grain for cracks.
- Check brown rice immediately after husking.
- Check machine feed rate.
- Record whitener pressure or relevant settings.
- Measure or compare grain temperature.
- Inspect screens and milling components.
- Change one variable.
- Run another test.
- Compare broken rice percentage.
Related Reading
Sources & Technical References
References support general principles. Machine-specific settings require the matching manufacturer manual.
- Commercial rice milling systems ↗IRRI Rice Knowledge Bank · Process-stage definitions and line arrangement.
- Paddy quality ↗IRRI Rice Knowledge Bank · Incoming grain quality and its effect on milling.