  We investigate the role of inhomogeneities in zero-range processes in
condensation dynamics.We consider the dynamics of balls hopping between nodes
of a network, and find that the condensation is triggered by the ratio k_1/k of
the highest degree k_1 to the average degree k. Although the condensate takes
on the average an extensive number of balls, its occupation can oscillate in a
wide range. We show that in systems with strong inhomogeneity, the typical
melting time of the condensate grows exponentially with the number of balls.
