Complex coacervates are liquid-liquid phase-separated droplets that are formed by the association of oppositely charged polyelectrolytes. In living cells, many membraneless organelles (MLOs) are formed in the same way, by phase separation of intrinsically disordered proteins and nucleic acids. However, the fate of nucleic acids in different MLOs varies significantly. In some MLOs, such as the nucleolus, RNA remains accessible and is actively processed, whereas others, such as stress granules (SG), act to safely store RNA and protect it from degradation. Despite the crucial role of MLOs in cell organization and survival, the link between their physicochemical properties, such as protein crowding, and their function remains poorly understood. Here, we demonstrate a systematic in vitro approach to study the fate of RNA in different types of MLOs. We mimic the environment inside the nucleolus by using nucleophosmin (NPM-1). In parallel, we mimic the environment in stress granules by using G3BP1, one of the key proteins in SG formation. By comparing the uptake, conformation and accessibility of different RNAs in these two model MLOs, we aim to gain insight into the properties of biomolecular condensates in life.