A process includes: (a) providing an initial cellulose ether powder containing 0.5 to 10 weight-percent water based on total cellulose ether powder weight; (b) heating the initial cellulose ether powder to a temperature in a range of 30 to 130 degrees Celsius; (c) before, during and/or after heating in step (b), adding solid base to the cellulose ether powder and mixing with the initial cellulose ether powder to form a cellulose ether/base mixture; (d) adding volatile acid to the cellulose ether/base mixture and mixing; and (e) allowing the volatile acid to hydrolyze the initial cellulose ether to form a final cellulose ether having a lower viscosity than the initial cellulose ether.