Self-raising flour

Flour is a substance, generally a powder, made by grinding raw grains or roots and used to make many different foods. Cereal flour is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history. Wheat flour is one of the most important ingredients in Oceanic, European, South American, North American, Middle Eastern, North Indian and North African cultures, and is the defining ingredient in their styles of breads and pastries.

Wheat is the most common base for flour. Maize flour has been important in Mesoamerican cuisine since ancient times and remains a staple in the Americas. Rye flour is a constituent of bread in central Europe.

The English word "flour" is originally a variant of the word "flower" and both words derive from the Old French fleur or flour, which had the literal meaning "blossom", and a figurative meaning "the finest". The phrase "fleur de farine" meant "the finest part of the meal", since flour resulted from the elimination of coarse and unwanted matter from the grain during milling.

The earliest archaeological evidence for wheat seeds crushed between simple millstones to make flour dates to 6000 BC. The Romans were the first to grind seeds on cone mills. In 1879, at the beginning of the Industrial Era, the first steam mill was erected in London. In the 1930s, some flour began to be enriched with iron, niacin, thiamine and riboflavin. In the 1940s, mills started to enrich flour and folic acid was added to the list in the 1990s.

...
Wikipedia