Moisture Requirements for Export Pulses

Of every parameter in a pulse contract, moisture is the one that deserves the most deliberate thought and usually gets the least. Purity can be improved with another cleaning pass. Colour can be improved with a sorting pass. Broken grain can be screened out. Moisture is different: once the bags are stuffed and the container is sealed, the water in the grain is inside the box for the whole voyage, and nothing that happens afterwards will remove it.

What high moisture actually does

A sealed container crossing the Indian Ocean goes through a daily temperature cycle. The steel heats in the sun and cools at night, and the air inside cycles with it. Moisture evaporating from grain at the warm part of the cycle condenses on the coolest surface at the cold part — usually the container roof and walls — and drips back onto the cargo. This is container rain, and it is the mechanism behind most wet-damage claims on bagged agricultural cargo.

The higher the moisture in the grain, the more water there is available to make this cycle destructive. At the top of the cargo, where condensation lands, the result is caking, mould and discoloured bags. Elsewhere in the container, elevated moisture accelerates mould growth, supports insect development and degrades colour — mung beans in particular lose brightness noticeably.

Typical contract ceilings

These are conventional starting points, not universal rules. The right ceiling for a particular shipment depends on the transit time, the season, the humidity at the discharge port and how long the cargo will sit before it is used. A contract moving into a humid tropical port in the wet season justifies a tighter figure than the same product moving into a temperate port in winter.

Controlling moisture at origin

1. Check moisture at intake, on every delivery, before the crop is accepted for a particular contract.
2. Condition material that arrives above the target — sun drying on tarpaulins or drying floors, or mechanical drying where available.
3. Re-check after conditioning, because drying is uneven and a single reading on a mixed load is misleading.
4. Store conditioned crop where it cannot reabsorb moisture from the ground or from humid air.
5. Check again at final inspection before bagging, since the interval between conditioning and packing can be weeks.
6. Load into a container that is dry, clean and free of previous cargo residue, and use desiccant where the route and season warrant it.

Why measurements disagree

Moisture disputes are common, and most of them are not about dishonesty. Different instruments calibrate differently. Grain moisture is not uniform within a lot, so where the sample was drawn matters. Temperature affects readings on some meters. And moisture genuinely changes between loading and discharge as the cargo equilibrates with the air around it.

• Agree whether moisture is assessed at loading or at discharge — they are different figures and the contract should say which governs.
• Agree the method: a specified meter type, or an oven method as the reference where precision matters.
• Draw the sample properly. A reading from three accessible bags is not a reading on a container.
• Where independent verification matters, have the inspection company take the reading at the agreed point.

How sampling is done properly, and why it decides most quality arguments. Commodity sampling methods →