A generalized thermoelastic model for adhesion was developed to elucidate the mechanism of dissipation within the viscoelastic bulk of a hydrogel. Results show that in addition to the expected energy release rate of interface formation as well as the viscoelastic drag and viscous flow dissipation, the bulk composition exhibit dissipation due to phase inhomogeneity motion. The mixing thermodynamics of the matrix and solvent composition determine the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time dependent behavior since, given enough time, these inhomogeneities can be influenced by image forces at the interface causing migration, which may in turn, affect the dissipation at the interface. A nondimensional parameter is proposed to discern the dominant dissipation mechanism in hyperelastic contact detachment.