Recent advances in paper drying research have identified a phase-change process that offers significant improvements in drying rates and sheet solids contents. A fundamental study focusing on the hypothesized boiling process within the sheet required the development of an apparatus to perform boiling experiments in a bed of ceramic fibers. The apparatus is composed of a boiling cell, a heat supply system, a digital data acquisition system, and associated process control systems for control of heater surface temperature and cell pressure. Boiling curves measured with this system indicate that heat transfer is governed largely by the physical characteristics of the fiber bed. This paper presents a detailed explanation of the boiling apparatus.