Abstract: A system and method of processing laundry by the determination of surface tension in a dynamic environment for surfactant concentration in industrial laundry applications. The dosage system is able to control the surfactant concentration for a recycle wash tank and preferentially the washer tank using surface tension measurements, temperature control, and correlation to the percentage of active matter based on a full dose of a commercial surfactant for the wash runs. The dosage system preferably uses a surface tensiometer able to monitor surfactant levels and to constantly dose surfactant for use in subsequent washes.