Abstract: A continuous gas/steam ratio monitor is disclosed for use with a geothermal fluid source. A sample of the geothermal well steam flow is mechanically separated to eliminate condensate and treated with sulfuric acid to a pH between 3.0 and 5.0 to prevent H.sub.2 S and CO.sub.2 from dissolving into solution. Discharge of the steam occurs to a separating reservoir and then to a vertical condenser column having a lower condensate pool and an upper gas discharge outlet. The vertical condenser at its cooling fluid end is connected to an atmospheric heat exchanger to condense the steam close to the boiling temperature of water at the operating pressure (about 20-25 inches of mercury). Thus the condensate has the maximum tendency to liberate dissolved noncondensible gases. The upper discharge end of the column is cooled by a refrigeration unit and is kept close to the freezing point of water (about 33.degree. F.). Thus, most of the water vapor mixed in the gas is removed.