The process of separating grains from the chaff is called [[1]]. 

The term used to describe the process of separating grains from the chaff is winnowing. This process is typically carried out after threshing, which involves separating the edible part of the crop (seeds) from the inedible parts (stalks, husks, and chaff).

Winnowing is accomplished by throwing the mixture of grain and chaff into the air, allowing the wind to blow away the lighter chaff while the heavier grains fall back down into a collection container. This process effectively separates the chaff from the grains, allowing farmers to collect and store the edible part of the crop.