The present invention is directed generally to dry cell culture media or feeds in pellet formats which can be reconstituted into liquid media for culturing cells in vitro. Each pellet composition may comprise the same or a different composition; for example, different vitamins, amino acids, buffers, trace salts, pH, iron chelators, etc. The invention also relates to methods of making dry cell culture media by altering ratios of different pellet compositions, or, methods of making modular dry cell culture media, or customizing media formulations for growing a cell type using pellets. According to the invention, media pellets may be easier to handle either before reconstitution, during shipping and handling; and/or during reconstitution. Media pellets may be used in any container like bags including sterile, single use bags for preparing media formulations. The invention also relates to kits and culture systems using media pellets.