Machines having reversible food moving devices for making popcorn and other types of expanded food products are described herein. In one embodiment, a popcorn machine includes an auger that moves a mixture of raw corn kernels and cooking oil along a trough-shaped cooking surface. In this embodiment, the auger can cyclically reverse direction for a predetermined period of time before resuming rotation in the forward direction to facilitate favorable popping of the popcorn. In one aspect of this embodiment, the auger can rotate through a greater angle of rotation in the forward direction than in the reverse direction in each cycle, so that the auger progressively moves the unpopped corn kernels along the entire cooking surface until they ultimately pop and/or are dispensed into a suitable receptacle. In one embodiment, the popcorn machine can also include two or more heating zones to provide favorable popping characteristics.
展开▼
