Wheat is a cereal in the Gramineae or Poaceae family. The plant grows between 60 cm and 1.2 m tall and develops ears with groups of flowers, each having three to five flowers. After pollination, the mature flower remains closed, producing the wheat grain as fruit. The wheat grain is oval-shaped, more or less rounded and has a small brush on the upper and lower end. Grains of wheat vary in size, shape and colour, depending on the variety. They can be white, red, yellow or purple.
A grain of wheat is not homogeneous. It comprises several layers of different tissues in three main parts: the germ, the endosperm and the husk.
1. The germ is the most important part of the grain as it enables the plant to reproduce. The germ is usually removed when the grains are cleaned in flour mills, as it has a high fat content which might turn flour rancid. Wheat germ is also high in mineral salts, vitamins, protein and oil and is often sold in health food shops.
2. The endosperm is the second main part of the grain. It contains around 65 to 70% of starch as well as a protein substance (gluten) which is distributed in particles amongst the starch granules. Around 12 to 14% of the endosperm is made up of gluten, which helps to bind flour and water together when making bread dough.
3. The husk protects the grain from external hazards. It is milled separately and sold as wheat bran.
There are two main types of wheat: hard wheat suitable for hot, dry climates, and soft wheat which is grown in cool, humid regions. Hard wheat provides semolina for pasta and couscous, while soft wheat is used to make bread. Winter wheat is a variety of soft wheat which is sown in autumn to take advantage of the winter moisture, whereas late-growing summer wheat is sown after winter in regions with a harsher climate. In Europe, the French term froment refers to both varieties of wheat as well as to spelt.