Quality & Specification
Pulse Grading Explained
Why pulses are traded on contract specifications rather than numbered grades, how a lot is assessed in practice, and where the disagreements come from.
· 8 min read
Anyone arriving in the pulses trade from cereals notices the difference quickly. Wheat and maize move against national grade standards with defined numbered categories, published tolerances and official inspection. Pulses largely do not. They are traded on specifications negotiated between buyer and seller for each contract, supported where appearance matters by a physical approved sample.
This is not disorder. It reflects the fact that pulses serve very different end uses with genuinely different requirements, and that the visual parameters buyers care about resist standardisation. It does, however, place responsibility on both parties to write down what they mean, because "Grade A" or "premium quality" carries no fixed meaning across the trade.
What a grading specification contains
- Commodity, type and colour — including variety or colour class where it is commercially distinct.
- Origin and crop year.
- Moisture ceiling.
- Purity minimum.
- Foreign matter maximum, sometimes with a separate stone sub-limit.
- Admixture maximum.
- Damaged and discoloured maximum.
- Broken and split maximum.
- Insect-damaged maximum.
- Immature and shrivelled maximum.
- Size or count, where the commodity is traded on it.
- Cleaning level: machine cleaned, colour sorted, or hand picked.
- Whether an approved sample governs appearance, and who holds it.
Where grading actually happens
At intake
The first grading decision is whether to buy at all, and against which contract. A delivery is sampled, checked for moisture, obvious foreign matter, insect activity and admixture, and either accepted for the intended specification, diverted to a lower one or refused. Getting this wrong is expensive, because material that should never have entered the line consumes cleaning capacity and depresses the yield of everything blended with it.
On the cleaning line
The line performs grading physically. Screens separate by size, aspiration by weight, destoners and gravity tables by density, and optical sorters by colour. The settings at each stage are chosen against the contract, so the same crop can be run to two different specifications by changing the aggressiveness of the separation — with a corresponding change in yield.
At final check
A composite sample is drawn from the finished lot and assessed against the contract, and retained samples are kept so that any later discussion refers back to what was actually packed.
Size grading by commodity
| Commodity | Size basis | Commercial weight |
|---|---|---|
| Pigeon peas | Not normally size graded | Screening removes undersize and broken material only |
| Mung beans | Screen size in mm | Significant — a primary price factor |
| Kabuli chickpeas | Calibrated size band | Dominant — usually the largest single price driver |
| Desi chickpeas | Screen size | Moderate, alongside milling yield |
| Dry beans | Count per 100 g | Significant — contracted as a band |
| Cowpeas | Not normally size graded | Appearance and type dominate |
Why disputes arise
- Subjective parameters. "Discoloured" and "sound" are judgement calls, and reasonable assessors differ.
- Unrepresentative sampling. A sample from a few accessible bags does not describe a container.
- Different instruments and methods, particularly for moisture.
- Condition at arrival assessed against a specification written for condition at loading.
- Expectations that were assumed rather than written — colour type is the classic case.
How pigeon peas specifically are assessed and graded. Pigeon peas grading