Abstract: The invention relates to a probe for measuring volatile components in an aqueous solution, for example to determine the alcohol concentration of an aqueous solution, with a probe body with a continuous lumen and a membrane disposed transversely with respect to the lumen, which isolates the lumen from the outside, and with a semiconductor gas sensor disposed in a housing inside the lumen at a distance from the membrane forming a measuring chamber filled with air, said sensor responding to the gases permeating the membrane by changing its electrical resistance, with an open continuous pressure relief channel being provided for the outflow of the gases permeating into the measuring chamber on the side of the sensor and the measuring chamber facing away from the membrane, and the pressure relief channel being connected at one end through an opening to the measuring chamber and at the other end on the outlet side having an outlet opening of a size such that the volume flow of the gas permeating through the membran