Milk protein concentrates (MPC) are becoming a preferred source of protein in ready-to-drink dairy beverages. Calcium-mediated aggregation of proteins during storage is one of the main reasons for the failure of these beverages. In the current study, 2 batches of each MPC85 (control), 20%-calcium reduced (MPC-20%), and 30%-calcium reduced (MPC-30%) were evaluated in 2 phases and in duplicate. In both the phases, 6 MPC powders were reconstituted to 8% protein solutions, added with 0, 0.15, and 0.25% concentrations of sodium hexametaphosphate (SHMP), and analyzed for heat stability by measuring heat coagulation time (HCT) at 140°C. In phase I, MPCs were reconstituted in distilled water and pH was adjusted to 7 before 3 concentrations of SHMP were added. MPC-30% and MPC-20% exhibited the highest HCT of ~32 min at all levels of SHMP addition while MPC85-Control has the least HCT time of ~21–25 min at 0 and 0.15% SHMP. HCT of control (28.06 min) at 0.25% SHMP and HCT of MPC-30% (32.79 min) and MPC-20% (30.96 min) at 0% SHMP were not significantly different (P > 0.05). In phase II, MPCs were reconstituted in a model dairy beverage formulation consisting, 10.26% of a mixture of gums (gellan gum, carrageenan, cellulose gel, and microcrystalline cellulose), maltodextrin, and sugar along with, 0.12% potassium citrate. Formulations were homogenized and treated with 3 concentrations of SHMP after adjusting pH to 7. It was found that the presence gums and sugar adversely affected the HCT of formulated model beverage. Control at 0% SHMP and MPC-20% at 0% SHMP exhibited the highest HCT of 8.86 and 8.37 min, respectively and the HCT is not statistically different (P > 0.05). This study shows the possibility of reduced levels of phosphate addition by using calcium reduced MPCs.