Corrosion inhibitor blends including one or more ether compounds, one or more quaternary ammonium compounds, and one or more fatty acid amine condensates are disclosed. The corrosion inhibitor blends can be used in methods of inhibiting corrosion of a metallic surface in a geothermal process. In one method, an effective amount of a corrosion inhibitor blend may be added to a production well in a geothermal process. In another method, an effective amount of a corrosion inhibitor blend may be added to a geothermal medium, which could be, for example, steam or liquid brine.