An arrangement for monitoring a freeze drying process includes product condition sensors for product condition measurement within product vials. The product condition sensors are bimetal junctions deposited on a substrate using an ink jet printing process. The substrate may be a flexible film applied to an interior surface of the product vial, or may be the vial surface itself. The bimetal junction may be printed using a roll-roll inkjet printing process with metallic nanoparticle inks. Multiple closely-spaced bi-metal junctions are provided in each measurement vial. Data from the sensors is transmitted to a data collection point via short range wireless digital communications. The location of a sublimation front may be calculated for each measured vial, and the freeze drying process may be controlled using the data.