Abstract: A direct contact steam injection heater that allows shear to be adjusted by modifying a lateral position of a movable combining tube. The movable combining tube includes a rack on an outer surface of the combining tube that engages a movable lever arm of an adjustment mechanism. The pivoting movement of the lever arm moves the combining tube in a lateral direction to adjust the shear in the product being heated. The combining tube is supported in a housing by a pair of lateral bushing and a pair of end seals prevent product from entering the combining tube housing. The lever arm is coupled to a worm gear shaft such that rotation of the worm gear shaft creates pivoting movement of the lever arm and lateral movement of the combining tube.