We consider the problem of makespan minimization on a flexible flow shop with k stages and ms machines at any stage. We propose a heuristic algorithm based on the identification and exploitation of the bottleneck stage, which is simple to use and to understand by practitioners. A computational experiment is conducted to evaluate the performance of the proposed method. The study shows that our method is, in average, comparable with other bottleneck-based algorithms, but with smaller variance, and that it requires less computational effort