A moisture limit at loading is what a supplier can control. The condition on arrival also depends on the pack, the container and the voyage. Agree the limit, the method and the point of measurement together, and choose the pack to suit the product.
Moisture is the quality line nobody sees. It changes the weight you pay for, the risk of mould in store and the nicotine figure on the certificate. It is also the line that moves after the supplier is done with the cargo. This article covers what is being measured, how the pack protects it and where a shipment goes wrong.
What "moisture" is measured as
Two methods dominate and they are not the same measurement. CORESTA Recommended Method 76 records the mass lost when a sample is dried in a forced-draft oven at 100 °C ± 1 °C for three hours. That is oven volatiles, and it can include small amounts of compounds other than water. ISO 6488 is a Karl Fischer method that measures water specifically. For many samples the two sit close together. A contract should still say which one applies, and not just "moisture 12% max".
Why leaf moves
Tobacco is hygroscopic. It takes up and gives off water vapour until it balances with the air around it, and that balance shifts with humidity and temperature. Three consequences follow.
- In a humid climate, open material gains weight. Packed leaf does not stay at the moisture it had on the day of loading unless the pack and container keep the air out.
- Material that is too dry breaks. Brittle lamina makes extra scrap and fines.
- Material that is too damp invites mould and some storage pests.
Scrap, stems and dust have far more surface area than whole leaf, so they follow the air faster. Dust in particular needs a sealed bag and a dry route to the ship.
What a loading limit promises
Indileaf's limit across leaf, lamina, scrap, stems and dust is moisture not above 12% at loading. The words "at loading" are important. They describe the condition when the material leaves the packing area. They do not describe the condition after a sea voyage through warm, humid ports. Buyers should write the limit, the method and the point of measurement into the contract so that nobody argues later about when the number was meant to apply.
| Item | What to agree |
|---|---|
| Limit | A maximum, for each product |
| Method | CRM 76 or ISO 6488, named |
| Point of measurement | At packing, at loading or on arrival |
| Sampling | Per an agreed procedure, sealed airtight and labelled |
| Referee | An independent laboratory, named in advance |
| Weight basis | As received, or adjusted for moisture |
Choosing the pack
Packing is the first line of defence. In practice the choice follows the form of the material.
- Leaf, lamina and scrap go in new C48 cartons of about 150 kg. A carton gives stacking strength and keeps the load tidy. It is not vapour-proof, so condition depends on the container and the voyage as well.
- Dust goes in HDPE bags of 25 to 40 kg. Fine material takes up water quickly and leaks easily, so a sealed bag is the sensible form. Buyers who want an inner liner can specify one.
- Stems go in cartons or HDPE bags as agreed, with HDPE bags for cut or fine stems.
Mark every unit with the lot, product and net weight. If a claim comes later, that mark is how the lot is found. If cartons or bags are palletised, wooden pallets and dunnage for export should be treated and marked to ISPM 15. Check this before loading, because a missing mark can hold the cargo at the destination.
The container is part of the pack
A closed steel container is a hot, sealed box by day and a cold one by night. Air inside holds water vapour. When the steel cools, that vapour condenses on the roof and walls and drips down onto the cargo. Traders call it container rain, and it is a main route for rewetting in transit. The CTU Code, the international guidance on packing cargo transport units, addresses condensation and cargo sensitive to moisture.
Before loading, check that:
- The floor, walls and roof are dry, clean and without holes. A container that shows light through the roof is a rejected container.
- Loading is not done in rain, and cartons or bags are kept off wet ground.
- The cargo is stable and tightly stowed, so units do not shift and tear.
- Pallets and dunnage carry the ISPM 15 mark where wood is used.
Monsoon-season loading calls for extra care at every step, from the godown to the quay. Wet material is nearly impossible to fix once it is sealed in a box.
When arrival moisture is disputed
An arrival result does not settle much on its own. The questions are what the moisture was at loading, what the sample looked like when it was drawn and how it was sealed. This is where a sealed retained sample from the lot at origin pays for itself. Indileaf keeps one for every lot. Compare like with like: the same method, taken at the point your contract names. Where the two results still disagree, a referee laboratory settles it.
The products page shows the packing for each form, and you can request a sample to see the pack and test the moisture yourself.
Frequently asked questions
What moisture should tobacco be shipped at?
There is no universal figure. It depends on the product, the process and the length of the voyage. Indileaf states moisture not above 12% at loading, and buyers should set their own maximum and method in the contract.
Can a supplier promise a moisture figure on arrival?
Not by itself. The supplier controls the condition at packing and loading. Arrival condition also depends on storage, the container and the voyage, so agree what is measured and where.
Why does condensation form inside a container?
Warm, humid air in a closed container cools when the steel cools, and the water vapour condenses on the cold surfaces. Dry containers, careful stowage and suitable packing reduce the risk.
