The invention pertains to a method for preparing a product for fermentation comprising the steps:i. sterilizing and expanding a substrate to obtain a sterile expanded substrate,ii. cooling and inoculating the sterile expanded substrate by contacting the sterile expanded substrate with a cooling medium and an inoculum to obtain a cooled inoculated substrate.The expansion step can be performed using techniques from the state of the art known as popping or puffing.The method can be performed in standard equipment and is very flexible in its use. Furthermore, the method allows reducing the time and energy necessary to obtain a product for fermentation, such as solid state fermentation.
