A hydraulic hinge for the lid of a food serving vessel in a buffet restaurant includes a hinge block, a shaft pivotally mounted to the hinge block, an annular hydraulic chamber within the hinge block and at least partially surrounding the shaft, and a one-way valve having an inlet port and an outlet port each communicating with the hydraulic chamber and allowing hydraulic fluid to flow from the inlet port to the outlet port but not vice versa. The hinge further includes a rotary piston extending from the shaft across the annular hydraulic chamber and adapted to pivot with the shaft between the inlet and outlet ports and comprising a flow restrictor allowing hydraulic fluid to flow relatively slowly therethrough. This prevents the lid from dropping after patrons release the lid.