How shelf cooling rate influences the temperature at which ice nucleates.
Primary drying gets much of the emphasis in freeze-drying because it’s the longest step. But the cooling and freezing steps affect every part of the process, and shelf cooling rates differ between scientists and companies in ways that can lead to different cycles and total drying times.
Lab results across four vial sizes show what changed with slower and faster cooling, along with a finding that questions whether ice always nucleates randomly across a shelf.
