The Composition of a Grain of Wheat 
Endosperm
This is name given to the interior of a wheat kernel and makes up about 83% of the whole grain of wheat. The endosperm, once it has been ground down to a powder, is flour.
Semolina
This is made from the endosperm with the mill set to produce coarser flour particles.
Bran
This is the outer layers of the wheat grain which are removed during the milling of white flour. About 14% of the wheat kernel is the bran. Some bran is rolled to make it flaky and sold for human consumption with the rest being used in animal and poultry feed. Wholemeal flour contains all the naturally occurring bran.
Germ
The GERM is the part of the grain which would sprout if it was planted as a seed. It is packed with nutrients and protein with which to nourish a new plant. During milling the germ is usually separated from the rest of the wheat grain because its fat content limits the shelf life of the flour. It is occasionally used as a dietary supplement or sold as animal feed.
Couscous
Couscous is not part of the wheat grain but a kind of precooked, dried pasta prepared from 100% Durum Wheat Semolina. The granular particles are about 1-2mm in diameter and require cooking.
Bulgar
Bulgar is pre cooked chopped wheat. It has been traditionally prepared for centuries by boiling the grain until thoroughly cooked, then drying before cracking the hardened kernels into coarse pieces. As bulgar wheat is pre cooked it only needs re-hydration before serving.
Durum
This is not part of wheat but the name of a type of wheat. Semolina milled from Durum wheat is often used for pasta making.
