Combine harvester with near-infrared grain sensor

A combine harvester (10) is provided that includes a grain elevator (60) for transporting and elevating harvested grain from a lower point near a downstream end of a cleaning zone (26) of the combine harvester to a higher point near a grain inlet of a grain tank (28) of the combine harvester (10). A grain elevator (60) includes a paddle ring, a drive mechanism, an elevator housing (62), and a sensor assembly (70). The paddle ring includes a plurality of paddles (72) for carrying harvested grain. A drive mechanism is arranged for driving the paddle ring and thereby moving the paddle (72) upward at a first side of the paddle ring and downward at a second side of the paddle ring. An elevator housing (62) surrounds at least a portion of the paddle ring. The sensor assembly (70) comprises an NIR sensor (80) for detecting a characteristic of the harvested grain and a sensor window (82) arranged for enabling infrared light to propagate between the NIR sensor (80) and the harvested grain. A sensor window (82) is embe