A method for controlling condensation of hydrogen peroxide at a preselected temperature within a sealed sterilization chamber including an article to be sterilized includes the steps of applying to the sealed chamber a vacuum of a first pressure sufficient to evaporate, at the preselected temperature, an aqueous solution of hydrogen peroxide of a first concentration. The hydrogen peroxide solution is then evaporated into a water vapor component and a hydrogen peroxide vapor component. The evaporated solution is injected into the sealed chamber in repeated pulses. The injecting is terminated once a preselected second pressure, higher than the first pressure, is reached in the chamber. The pulse volume is selected to allow selective control of the condensation of the hydrogen peroxide vapor component to achieve a layer of micro-condensation of hydrogen peroxide on the article, which layer has a second hydrogen peroxide concentration higher than the first hydrogen peroxide concentration.
