Cold extrusion 3D food printing is an emerging technology which enables the manufacture of food in different shapes and structures and offers huge potential for personalised food products. This study investigates rheological properties and printability (shape fidelity) of food-grade hydrocolloid pastes. From this study, it was found that if the phase angle is in the range of 3°–15° and the relaxation exponent is in the range of 0.03–0.13 the paste material is printable, which means that it can support its own-weight if printed. As the demand for inks for 3D printing increases, rheological measurements can rapidly assist with the development of new ink feedstocks. Display omitted •3D printing of hydrocolloids is influenced by their rheological properties.•Thixotropic hydrocolloid systems were used as a model for food 3D printing.•Over 50 combinations (concentration/type) of hydrocolloids were analysed and their rheological properties were reported.•Phase angle and relaxation exponent are used to get insight on 3D printing of hydrocolloids.•This design rule can be used to identify food formulations with tailored made properties for use in food 3D printing.