About pearl millet

Pearl millet is a highly nutritious staple cereal, produced on small farms by millions of people in sub-Saharan Africa. The plant requires no irrigation and can grow in the harshest conditions.

Three Nigerian women threshing pearl millet panicles by hand using a large mortar and pestles.
Photo by Donna Cohn, 2014.

But threshing and separating the edible grains from the panicle is a slow and labor-intensive process. Practices vary by region and ethnicity of the farmers, but in general women do the work of extracting the grain by hand, with repeated cycles of pounding and winnowing.

 

Illustrations of a field of pearl millet; a single panicle, with some of the florets removed; and a single floret, alongside some individual seeds.
Illustration by T.X. Watson, 2015.
Pearl millet grows on a long stalk, with a cylindrical seed head called a panicle. Within
the panicle, the edible grains are held tightly within fibrous glumes, which form florets that grow around a central stem. With a grain like wheat, you can just shake the stalk and the grain falls off. The grains of pearl millet are much more tenacious than other grains. They must be knocked very hard to come loose.
Illustration of a variety of types of pearl millet, of different sizes and shapes.
Illustration by T.X. Watson, 2015.

An additional challenge of this project is that pearl millet varies widely in its shape and physical behavior based on land race and growing conditions. For example, Namibian pearl millet panicles are much thicker than those available for experimentation in Massachusetts, and Nigerian panicles are much longer.

When the time and energy cost of threshing and winnowing the millet is reduced, it also reduces the health burdens and stress placed on the women responsible for the task. We aim to make a thresher with a low cost and simple design, in order to make a universal improvement to the processing of an important and nutritious crop that has the potential to improve global food security.

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