In the non-equilibrium condensate of exciton-polaritons, pumping dynamics is predicted to lead to spontaneous formation of a rotating vortex lattice. This has, however, so far not been observed. This could be either because the vortex lattice fails to form, or because moving vortices are extremely difficult to detect. Here I give an introduction to exciton-polariton condensates, and present an experimentally feasible method by which a rotating vortex lattice may be detected. I also demonstrate the robustness of the lattice to experimentally realistic imperfections.