The steam method, also known as autoclaving, involves heating the granules with steam until they reach between 300-370 oC, at which point the granules undergo expansion and exude a natural resin from the suberin, driving the agglomeration or binding. Once removed there is a noticeable toasted smell for some time (which will eventually dissipate – but it will take some time). The autoclave material is 100% totally natural and considered an ecological agglomerate. Due to the granule expansion, they tend to have a very low density, which in turn gives it high insulating properties, and greater water resilience as there is no external binder.