A system for drying a wet lactose product stream includes a disperser configured to disperse agglomerated lactose particulates in a wet lactose stream into a dispersed wet lactose stream. A back-mixed partial drying zone is configured to at least partially dry the dispersed wet lactose stream by recirculating a partially dried lactose stream with the dispersed wet lactose stream. A plug-flow secondary drying zone is configured to dry the partially dried lactose stream to generate a substantially dried lactose stream.