Here we systematically varied the composition of the relative amounts of ligand (2-methylimidazole), metal precursor (Zn(OAc)2∙2H2O, and protein to prepare a series of protein@ZIF biocomposites. The effect of post synthetic treatments (i.e. washes with water or water/ethanol) was investigated. The XRD data of the examined samples were used to construct ternary diagrams. Five different phases were identified. The encapsulation efficiency (of bovine serum albumin and insulin) were phase dependent.