Jet agglomeration has been used in the food industry for several years to produce agglomerates with favourable instant properties from fine powders. In a jet agglomeration plant, freely moving, wetted particles are made to collide with each other to form agglomerates. Agglomeration occurs if the relative kinetic energy of the particles can be dissipated by the viscous liquid layers on their surfaces. This size enlargement process can only be understood if the forces between the colliding particles, called dynamic adhesion forces, can be described. Following a description of the jet agglomeration process, an indirect approach to this problem is presented which uses an experimental set-up allowing determination of the adherence probability of spheres colliding with wetted surfaces.