The invention relates to a method for making a powder containing crystalline particles of glucopyranosyl-alditols, including the continuous mixing of a glucopyranosyl-alditol syrup with a dry matter content of at least 80% by weight and a glucopyranosyl-alditol content of at least 95% by weight, preferably of at least 98% by weight based on dry matter, the mixing being carried out by simultaneously dispersing the glucopyranosyl-alditol syrup and germs containing glucopyranosyl-alditols in an open rotary container containing (glucopyranosyl-alditol)-based granules, whereby the glucopyranosyl-alditol syrup and the germs containing glucopyranosyl-alditols are mixed at the surface of the (glucopyranosyl-alditol)-based granules contained in the container, recovering the (glucopyranosyl-alditol)-based granules from the container and crystallizing the glucopyranosyl-alditols contained in the granules, the (glucopyranosyl-alditol)-based granules in the container being kept in motion by rotating the container.