This paper presents Salt, a distributed database that allows developers to improve the performance and scalability of their ACID applications through the incremental adoption of the BASE approach. Salt’s motivation is rooted in the Pareto principle: for many applications, the transactions that actually test the performance limits of ACID are few. To leverage this insight, Salt introduces BASE transactions, a new abstraction that encapsulates the workflow of performance-critical transactions. BASE transactions retain desirable properties like atomicity and durability, but, through the new mechanism of Salt Isolation, control which granularity of isolation they offer to other transactions, depending on whether they are BASE or ACID. This flexibility allows BASE transactions to reap the performance benefits of the BASE paradigm without compromising the guarantees enjoyed by the remaining ACID transactions. For example, in our MySQL Cluster-based implementation of Salt, BASE-ifying just one out of 11 transactions in the open source ticketing application Fusion Ticket yields a 6.5x increase over the throughput obtained with an ACID implementation.