Freeze-drying is an excellent way of drying thermally sensitivematerials and preserving thermally labile compounds. It is ex-tensively used in the pharmaceutical and biotechnology indus-try to produce active pharmaceutical ingredients (e.g., smallmolecules and proteins), which then can be conveniently dis-tributed and stored. Freeze-drying is also used in other sec-tors, for instance, in food industry (instant coffee), bacteriology(strain conservation), or chemical synthesis. Moreover, freeze-drying is a versatile means for processing of reference materi-als (RMs) for various application fields (e.g., clinical chemistry,food, and environment). Such RMs and especially certified RMs(CRMs) are important tools enabling laboratories all over theworld to deliver accurate measurement results of demonstratedreliability.1–3Considering the major efforts required for planning, process-ing, characterizing, and certifying a RM, the production of largeand stable batches is preferred, so that the CRM is available forseveral years after production. To achieve the desired long-termstability of biological materials, removal of water is essential.Freeze-dried materials can be kept for many years for most ma-trix/analyte combinations, provided that they are stored at anappropriate storage temperature. Obviously, similar require-ments apply for many pharmaceutical products with respect