A new mixer is designed for mixing a phenolic solution into water. The mixer design is such that it can be easily adjusted for the controlled mixing of a specific compound within a certain time. This paper describes the working principle of the mixer as well as a suitable characterization method for the mixer. Measurement results are presented which show the correct working of the mixer. A quantitative measure is introduced to express the extent of mixing performed by the mixer. The characterization method allows the measurement of the flow rate, pressure drop and extent of mixing.