⚡ QUICK ANSWER
Your main container desiccant options are calcium chloride, silica gel, clay and molecular sieve. For full ocean containers, calcium chloride is the standard because it absorbs many times more moisture than the others and keeps working across a long voyage. Within calcium chloride, you then choose a format — pole, hanging strip, blanket or in-box — to match how your cargo is stowed. Silica gel and clay are better kept for small sealed packages, not the whole container.
📊 KEY FIGURES
• Calcium chloride absorbs up to ~200–300% of its weight — roughly 10x silica gel (~20–30%).
• Formats: pole, hanging strip, blanket / sheet, and in-box sachets.
• Cargo most at risk: textiles, food, coffee, leather, electronics, machinery.
• A 40ft container encloses roughly 67 m³ of air that cycles through daily temperature swings.
What container desiccant options are available?
“Desiccant” covers several different materials, and they are not interchangeable for container shipping. The four you will come across are:
| Option | Capacity | Best for |
|---|---|---|
| Calcium chloride | Very high (~200–300%) | Full ocean containers, long / humid voyages |
| Silica gel | Low (~20–30%) | Small sealed packs inside cartons |
| Clay / bentonite | Low (~20–30%) | Low-cost, short, dry routes |
| Molecular sieve | W (~20%) | Very low target humidity, specialist use |
For a full container, calcium chloride is the default; the others suit small-package or niche cases.
Why calcium chloride for a full container?
A shipping container heats up by day and cools at night, so water vapour repeatedly condenses on the ceiling and walls and drips onto cargo — “container rain” or “cargo sweat.” Over a multi-week voyage this releases far more moisture than a low-capacity desiccant can hold.
Calcium chloride chemically absorbs water and locks it away as a gel, so moisture removed early in the voyage stays removed. Its very high capacity is why it is the standard option for containerised freight, while silica gel and clay are better reserved for small sealed packages.
Which calcium chloride format fits your cargo?
Once you have chosen calcium chloride, the format should match how the container is loaded:
- Pole / stick — stood in the void spaces between pallets; efficient for palletised cargo.
- Hanging strip — clipped to the lashing rings high on the walls, where condensation forms first.
- Blanket / sheet — laid over or around the cargo; good for full loads and irregular stows.
- In-box sachet — smaller units inside individual cartons for a second layer of local protection.
Many shipments combine formats — for example hanging strips for the container plus in-box sachets for sensitive items.
How do you choose the right option?
Work through it in order:
- Material — calcium chloride for full containers; silica gel only for small sealed packs.
- Format — match pole, hanging or blanket to your stow.
- Quantity — based on container size, voyage length and cargo moisture.
- Supplier — one that can show verified test data, the formats you need, and route-based dosage support.
SUPER DRY offers the full range of calcium chloride formats — pole, hanging, blanket and in-box — with dosage guidance for your specific cargo and route.
Frequently Asked Questions
What are the different types of container desiccant?
The main options are calcium chloride, silica gel, clay / bentonite and molecular sieve. Calcium chloride has by far the highest capacity and is the standard for full ocean containers; the others suit small sealed packages or specialist low-humidity uses.
Which container desiccant is best for my cargo?
For a full container, choose calcium chloride, then pick a format — pole, hanging, blanket or in-box — to match how the cargo is stowed. Silica gel is better kept for small sealed packages inside the container.
What is the difference between pole, hanging and blanket desiccants?
They differ in placement: pole desiccants stand in pallet voids, hanging strips clip high on the walls where condensation forms first, and blanket / sheet desiccants lay over the cargo for full loads. All can use the same calcium chloride.
Can I mix desiccant types in one container?
Yes, and it is common. Calcium chloride formats do the main work for the container, while in-box silica gel or calcium chloride sachets add local protection for particularly moisture-sensitive items.