Formulation scientists employed in the biopharmaceutical industry face the challenge of creating liquid aqueous formulations for proteins that never had evolutionary pressure to be exceptionally stable or soluble. Yet commercial products usually need a shelf life of 2 years to be economically viable. The research done in this field is dominated by physical chemists who have developed theories like preferential interaction, preferential hydration and excluded volume to explain the mechanisms for the interaction between salt, small organic molecules and proteins. This review aims to translate the research findings on protein stability and solubility produced by the physical chemists and make it accessible to formulation scientists working within the biopharmaceutical industry.