| grade | complete grain rate (%) | damage rate (%) | impurity (%) | moisture (%) | color and odor | |
| total | thermal damage particles | |||||
| first grade | ≥95 | ≤1 | ≤0.2 | ≤1 | ≤13 | normal |
| second grade | ≥90 | ≤1 | ≤0.2 | ≤1 | ≤13 | normal |
| third grade | ≥85 | ≤1 | ≤0.5 | ≤1 | ≤13 | normal |
| fourth grade | ≥80 | ≤1 | ≤1 | ≤1 | ≤13 | normal |
| fifth grade | ≥75 | ≤1 | ≤3 | ≤1 | ≤13 | normal |
| substandard | <75 | ― | ― | ― | ― | normal |