Materials and Concerns
Tiny Styrofoam pellets are the traditional filling for bean bag chairs. The pellets are so small and light that they can be swept away by a slight breeze. When pouring your light filling materials like Styrofoam pellets into your case or cases, it is important to do so in a wind-free environment. Close all windows, turn off all fans, and discourage anyone present from walking by. Styrofoam packing peanuts can be used comparably, with similar wind concerns.
Other filling materials include dried beans or rice. While the novelty of having a literal bean bag chair may be appealing, using food materials as a filler can be expensive in the quantities necessary. Additionally, insects, mice and other pests can be drawn to and infest bean, rice, or other grain-filled bean bag chairs. Feathers from old pillows or down from old jackets can be used, but have a tendency to poke through fabric of the chair.
The easiest method of filling a bean bag chair is to pour the filling from a bag directly into the opening of the bean bag chair. This method requires at least two people, one to hold the opening of each bag. This method offers minimal exposure to the outside environment, which means minimal chance of spilling.
It is recommended that bean bag filling be put inside a case or liner. This intermediary layer acts to help keep the filling inside the chair. It is also an easy way to fill the chair. Take your filling material and place inside a plastic or cloth bag, filling it so it is firm but not full, much like the chair itself should be. These smaller bags are inserted through the seam, which is then sewn or zipped shut. While plastic is likely cheaper, cloth bags offer the benefit of additional durability.
The bag should be filled slowly. After adding a fair amount of filling, close the bean bag up and have a seat. The pressure will settle the filling and push out any remaining air. If the bag is too soft or loose, simply add more filling until the chair meets your preferences.