The stacks depicted in the series are commonly referred to in English as hay, wheat or grain-stacks. In reality they stored sheafs of grain primarily for bread—so wheat [or possibly barley or oats]—and not hay, an animal food. The stacks were a way of keeping the sheafs dry until the grain could be separated from the stalks by threshing. The local method of storing and drying unthreshed-grains was to use straw, or sometimes hay, as a thatched 'roof' for the stack, shielding the wheat, barley or oats from the elements until, once dry-enough, they could be threshed. The threshing machines then traveled from village to village. Thus, although the grain was harvested and the stacks were built by July, it often took until the following spring or even later—so through all the light and atmosphere changes of summer, autumn, winter and spring—for all the stacks to be reached by the threshing-machines. Grain storage/drying-stacks like these became common throughout Europe in the 19th century and survived until the inception of combine harvesters. Although the shapes of stacks were regional, in Normandy, where Giverny is situated, it was common for them to be round with quite steeply-pitched thatched 'roofs'—just as Monet painted.