Freezing process design for the Janssen COVID-19 vaccine was carried out as per the governing standard operating procedures, i.e., by performing engineering runs at different storage temperatures in order to identify suitable operating conditions, coupled with extensive quality control testing to verify stability. After identifying supercooling as potential design challenge, constitutive experiments were carried out to characterize the supercooling in greater detail. Note that these experiments preceded the development of the model presented within this work.