The effectiveness of blended learning is dependent upon the combination of learning activities, complemented by information communication technologies and the availability of opportunities for face-to-face communication. This paper proposes a filtering approach to assist lecturers in combining learning activities within a blended learning environment. The filters focus on improving both the richness and smoothness of the learning blend. The filtering approach is demonstrated with examples taken from a module supporting the teaching and learning of postgraduate research training. Changing the blend of activities in this module has improved the richness of the learning experience for both students and staff. The evolution of the blend is discussed and further issues to be addressed in the future of blended learning are identified.