Relaxing replica freshness has been exploited in database clusters to optimize load balancing. In this paper, we propose to support both routing-dependant and routing-independent refresh strategies in a database cluster with multi-master lazy replication. First, we propose a model for capturing refresh strategies. Second, we describe the support of this model in a middleware architecture for freshness-aware routing in database clusters. Third, we describe an algorithm for computing refresh graphs, which are the core of all the refresh strategies.