Green building materials have received increasing attention in recent years since they represent promising solutions on the path to achieving carbon neutrality in the civil engineering sector. One of the possibilities to decrease CO2 emissions from cement production is to avoid its use altogether and develop cement-free materials. Gypsum-based composites have the potential to play an important role in the market with building materials in the future. Nevertheless, their main disadvantage remains their low strength and poor water resistance, limiting their wider use. Moreover, water (physically and chemically bound) defines the performance and properties of such materials. Additionally, most of the analytical techniques require dried samples before analysis, which needs to be done, especially in the case of gypsum-based materials gently. This paper evaluates the effects of two different water removal techniques, namely direct drying and immersion in isopropanol, on the composition of gypsum-based materials consisting of gypsum, lime, and ceramic waste, with the help of scanning electron microscopy and mercury intrusion porosimetry. The amount of the released water from the studied samples was quantified, and the efficiency of the methods was compared. It was found that whereas the selected drying method had only negligible impact on the morphology and porosity refinement of the studied gypsum-based composites, a more significant amount of water from the samples was removed using immersion of the samples in isopropanol compared to direct drying at 50 °C, especially in the samples containing the highest amount of pozzolana active ceramic waste and lime. [ABSTRACT FROM AUTHOR]