Exporters often open a container to find cargo damp, mouldy or rusted — even though it left the factory perfectly dry. The culprit is container rain, and the solution is the right container desiccant. Here's how it works.
What is container rain?
During a voyage, temperatures swing between hot days and cold nights. Humid air trapped inside the container — from the cargo, packaging, pallets and the air itself — condenses on the cooler steel ceiling and walls at night, then drips back down onto the goods like rain. Over a long journey this causes mould, corrosion, label damage, caking and warping.
How container desiccants prevent it
Container desiccants adsorb the excess water vapour before it can condense, keeping the humidity inside the container low throughout the trip. They are typically hung on the walls or placed among the cargo as poles, strips, bags or blankets.
Which desiccant should you use?
| Desiccant | Best for |
|---|---|
| Silica gel bags | Higher-value or moisture-sensitive cargo |
| Clay desiccant | Economical protection for general cargo |
How much do you need per container?
Quantity depends on cargo type, packaging, transit time and route humidity. As a starting point, several kilograms of desiccant are commonly used per 20-ft container, with more for tropical routes or hygroscopic goods. Our desiccant quantity guide explains how to size it.
Extra steps that help
- Ensure cargo, pallets and packaging are dry before loading.
- Use moisture-barrier liners for sensitive goods.
- Distribute desiccant evenly rather than in one spot.
We supply container desiccants for packaging & logistics exporters across India and overseas. Request a quote with your route and cargo for a tailored recommendation.