To prevent moisture in a spice container, start before the container is loaded. Condensation, often called container rain, forms when warm humid air inside the container meets a cold surface, such as the roof when the ship moves into cooler waters. Spices that were not fully dry, or packed in damp bags, supply the moisture.
Once the container is sealed you cannot fix it. The measures that work all happen at the factory and at loading.
Where the moisture comes from
- The product itself. Spices that are above their moisture limit release water as they warm and cool.
- The packing. Jute or paper bags, pallets and cartons can absorb humidity, particularly in the monsoon.
- The container. Residual water, wet wood or a damp floor adds humidity.
- The air trapped inside at loading. In humid weather it carries a lot of water vapour that condenses when it cools.
Start with the product
Set a moisture limit in your specification and make the supplier test each lot before packing. A figure that is acceptable for sale may still be too high for a long voyage through warm and cool zones. See our notes on the typical moisture limit for whole seed spices as a reference for what is normal.
Let the product cool to ambient temperature before bagging. Hot product sealed in a bag creates its own condensation.
Prepare the container and the load
- Inspect the container before loading: check it is clean, dry, free from odour and has no holes or light leaks.
- Use kraft paper or a corrugated lining on the walls and roof, and a container liner where recommended.
- Use desiccants or moisture-absorbing products where they suit the product, in the right amount for the container volume.
- Use dry, clean pallets and avoid stowing bags directly on the floor.
- Do not load in rain, and close the container doors as soon as loading ends.
Are desiccants and liners enough?
They help but do not replace a dry product. A desiccant has a limited capacity and a liner only protects against some effects. For when each is worth it, see desiccants and container liners and how to prevent container rain in agri shipments.
Ventilated containers, where available, can suit some agri products. Ask the forwarder whether this suits your cargo and route, since a ventilated container is not a sealed one and has its own trade-offs.
What to ask your supplier to do
Put the moisture precautions into the purchase order so they are part of the agreement, not a favour. Ask the supplier to record the moisture reading for each lot, to confirm the liner and desiccant plan, and to photograph the empty container, the lining and the loaded container before the doors are sealed.
If a claim arises, those photographs and the lot test results decide whether the cause was the product, the packing or the voyage. Without them, the insurer and the supplier will each point to the other. See why quality drops after the first container for the wider pattern.
Next step
Most condensation claims trace back to loading day. We supervise container inspection, loading and sealing so you can see the conditions. To set this up, book a free sourcing review.