A simplified AM2 model was developed to characterize mussel solid-state anaerobic digestion. This model considers two different substrates for mussels’ degradation: the mussel meat and the mussel juice obtained after sanitization. This model was implemented to characterize the anaerobic degradation of Mytilus edulis species. This model was verified, implemented, and validated in 60L batch reactors in mesophilic conditions. Two different experiments were used to calibrate kinetics using reaction invariants and an interior point optimization method. A conditioning study and a sensitivity analysis were done and had shown a better sensitivity with delayed substrate injections throughout the experiment with a factor of 10. An 88.6% accumulation of methane yield of the BMP measurement was observed, corresponding to 57.7% volatile removal with a minimum mass balance of 96.1%. Additionally, the model proposed in this study was able to successfully predict the two characteristic methane yield peaks observed during solid-state anaerobic digestion.