A method and an apparatus are provided for aeration of organic material, wherein the organic material undergoes an aerobic composing process, such that air is caused to evenly penetrate the organic material. The organic material is first sealed in a vessel. Air is then delivered to the contents of the vessel such that an air pressure of from about 1 to about 1000 kPa above atmospheric pressure is maintained in the vessel. A pressure differential initially forms and is then allowed to equilibrate over a period of time, in which time air flows from areas of high pressure to areas of low pressure in the organic material thus ensuring that aeration is evenly distributed throughout the organic material.