Jute sack is the industry standard for packaging cacao and coffee despite of its several weak points. Why it was chosen? Simply because of three things. It is cheap, durable and porous. Tons and tons could be fumigated inside a warehouse. Its porous nature allows the entry of fuming agent, killing pest and thereby increasing its storage life. For cacao beans, it helps evaporate too much acidity from previous fermentation process.
These are the common cases with our cacao.
We often pray that it never rains during transport. Why? Because if it rains, our raw material is likely to get wet. We need to immediately re-dry it as soon as possible, else, will be unusable after two days. Fungi grows rapidly giving off flavors and putrid odors. The material high water holding capacity adds to the problem. It holds plenty, that it is wet long after the rain. A short and light rain might not be enough to wet the beans but the water trapped within jute will eventually transfer.
The next problem is moisture absorption. Cacao that was dried down to 7% moisture or below is hygroscopic. It rapidly gain moisture in high humidity places. Large warehouses can be equipped with dehumidifiers but cannot be expected with small time processors. The beans become denser with time if weather condition is unfavorable. Become moldy in worst cases. Note, the same bean batch with varying moisture levels roast differently.
It also permits odor absorption. Odors that may not be removed during processing. Nice if gets fruity aromas of apple, orange, mangoes and nuts. Nightmare if gasoline and diesel instead.
The last but not the least. Correction! It is last and the worst. Cocoa moth and coffee borer beetle are gate crashing like crazy. There are plenty of passages everywhere so it cannot be avoided. In previous experiences, a sack full never last for a month once infested. I never experience the same on fermented cacao though.
As of date, my current supplier packs the raw mat in double layered packaging. Jute sack layered with moderate strength PE bag. They are using jute sack only when the contents of tranpo container is nothing but cacao. Whichever is the case, I am immediately transferring them all to another jute sack lined with new PE bag.