A typical shipping container may be watertight, but it is not airtight – and this means that ultimately, it is still vulnerable to moisture damage.

Moisture control solutions – like our hyperdesiccant BirchSorb – are used in shipping containers to protect cargo from what is called “container rain”. Container rain is caused by moisture vapour in the air, which is released during temperature or humidity changes during a shipping journey.

Container rain causes 10% of product damage worldwide every year, and can cause destroyed packaging, mould, and damage to the cargo itself – but while all cargo is vulnerable to container rain, certain types of cargo are more at risk than others.


Once coffee beans reach a critical moisture level of 12.5% or higher, fungi and mould caused by container rain has the potential to render entire containers of coffee beans completely unfit for consumption.

Coffee is hygroscopic, which means it absorbs moisture from the air around it. This means that it is essential to choose powerful moisture control to protect coffee cargo. BirchSorb is able to absorb over 200% its own weight in moisture, eliminating any chance of cargo reaching critical moisture levels of 12.5% or above during a journey.


As wood – like many types of cargo, including paper and cardboard – always contains some amount of moisture, re-release into the air during transit is a big risk. Moisture can cause tremendous damage to wood cargo, weakening and warping.

However, this is not just a danger for wood cargo – many shipping containers are made of wood or fortified and braced with it, and will weaken upon exposure to container rain, leaving the cargo inside vulnerable. Unlike many other forms of moisture control, BirchSorb “locks in” moisture, preventing any chance for re-release into the atmosphere.


Metal is extremely vulnerable to moisture with risk of cosmetic damage spoiling the look of the cargo. However, the damage can be more than cosmetic – rust and corrosion can severely weaken metal.

While some shipping containers are made from wood, others are made of metal, but this means that the containers’ internal temperatures are even more vulnerable to humidity during shipping. However, BirchSorb is effective for up to 12 weeks, protecting cargo throughout the entirety of a journey – regardless of how many temperature changes occur during it.

BirchSorb is available worldwide – and now comes with a free trial, giving your business the opportunity to find out why so many companies rely on it.

About the author
By Birch

Global product, worldwide support

We work with our specialist distribution partners to offer unparalleled service and supply globally, whatever your requirement. If you want to talk rubber or plastics, coatings or adhesives just get in touch. Our distributors can speak your language - literally.

About Birch Chemicals


Sign up to the Birch Chemicals newsletter and stay up to date with industry news.

This field is for validation purposes and should be left unchanged.