A valve for dosing and mixing two fluids includes two respective inlet ducts, a double chamber for controlling the flows, at least one actuator configured to regulate the flow rates of the two fluids to be mixed, an electronic control unit and a Brix degrees optical sensor, arranged on the mixing duct of the mixture of the two fluids and operatively connected to the electronic control unit. The optical sensor is configured to send a measurement and control signal to the electronic control unit to drive the actuator so as to proportionally control the flow rates of the two fluids and, therefore, regulate the mixing ratio of the two fluids.