Process for the manufacture of a mesoporous product comprising the following successive steps: a) preparation of a slip comprising: a solvent, an additive, more than 4%, as percentage by volume based on the slip, of a powder formed of ceramic particles, b) oriented freezing of the slip, so as to form a block comprising ice crystals separated by walls, c) removal of the ice crystals from said frozen slip block, optionally removed from the mold, so as to obtain a porous preform, d) removal of the additive, so as to obtain a preformed mesoporous product, the additive and the amount of additive being chosen so that the additive is present in a mesopore-forming micellar phase in said walls, more than 25% by volume of said ceramic particles exhibiting a size less than twice the size of the micelles of said mesopore-forming micellar phase.