Inserter sealer system

An optimized system and method for application of liquid for moistening adhesive on envelope flaps as part of an automated mail production process. Envelopes with open envelope flaps are transported beneath a moistening brush so that an interior side of the flaps, having adhesive thereon, come into contact with a lower end of the moistening brush. A flow of liquid is provided from a liquid supply coupled to the moistening brush to keep the moistening brush wet as moisture is transferred to the envelope flaps. The rate at which liquid is regulated such that moisture is maintained on the brush and a selected quantity of liquid (a dose) is provided for each envelope flap that it moistened. The dose is automatically determined as a function of physical dimensions of the envelope flap, and to optimize sealing of the envelope without excess dripping.