A temperature measurement system for a gasifier may employ a first stage gasifier with a refractory wall that defines a first stage gasifier volume. A protruding refractory brick may protrude from the first stage refractory wall and into a gaseous flow path of the first stage gasifier volume. The temperature sensor may reside completely through the refractory wall, which may be a plurality of brick layers, except for a tip end of a temperature sensor that may reside in a blind or non-through hole within the protruding refractory brick. The protruding refractory brick protrudes beyond a normal wall surface of the plurality of brick layers that defines the first stage gasifier volume. The protruding refractory brick may have a face that forms an angle that is not 90 degrees, such as 45 degrees, relative to the gaseous flow path of the fluid stream through the first stage gasifier volume.