A portable fuel dilution meter and method includes a plurality of sample bottles each with a lid securable thereto and an absorbent material in the bottle. A housing includes a sample bottle receptacle and a hinged head unit over the receptacle including at least a first needle piercing the lid of a sample bottle loaded into the housing receptacle and extending into the headspace of the sample bottle when the head is closed. A vapor sensor is fluidly coupled to the first needle for analyzing vapors in the headspace of the sample bottle.