The present invention relates to a method for producing a powdered porous product from at least one starting powdery and/or viscous product, characterised in that it comprises the continuous following steps without exposing the product to open air : a) preparing the starting product in order to make it viscous; b) in a thermo-mechanical machine (10) for continuously realising transport and/or mixing functions of viscous products or dry-material rich products, lowering the viscosity of the viscous product without changing its dry-material content, by intimate mixing with a gas injected into the processing machine (10) and simultaneously initiating the porosity in the viscous product; c) continuously with the processing machine (10), statically or dynamically intensifying the intimate mixture of the viscous product with a gas in order to obtain an aerated and porous mass; and d), dividing said mass in order to obtain aerated and porous particles.