Barley. The grain of the poor, historically. The grain of the loaves and fishes. The coarse meal that ground the molars of habitual eaters of this bread until their nerves were exposed. We think of Jesus as human but also superhuman. We don't consider him with aches and pains of everyday life. The pain of the cross, yes. But did his mouth throb because his teeth had been abraded by a life of consuming barley bread?
Here's a little lesson about barley from the Food Network's Alton Brown, Good Eats style.