The Cocoon™ is a commercially available hermetic storage container that consists of two plastic halfs that are joined together with an air-tight zipper after the cocoon is loaded with sacks of the commodity to be stored.
(Cocoons are made by GrainPro. While IRRI is not endorsing a specific manufacturer, GrainPro is currently the only manufacturer of hermetic Cocoons we are aware of.)
Why is a Cocoon important and how does it work?
Compared to traditional storage systems, Cocoons have the following benefits:
Cocoons reduce the flow of both oxygen and water between the stored grain or seed and the outside atmosphere. When properly sealed, respiration of grain and insects inside the bag reduce oxygen levels from 21% to 5%. This reduction reduces live insects to less than 1 insect/kg of grain without using insecticides - often within 10 days of sealing. The stablized moisture inside the cocoon prevents wetting and drying of grain. This reduces the extent of grain cracking and so head rice recoveries are higher upon milling.
How to store your grain in a cocoon
For details on how to load the Cocoon refer to the manufacturers manual. They come in different sizes and configurations e.g. for bulk or bag storage. Some general guidelines include:
While the technology is simple users sometimes still have bad experiences when the oxygen levels are higher than expected. This is often due to poor management. The following points are important.