Flour extraction refers to the process of extracting flour from grains, typically wheat. It involves milling the grains to separate the outer layers (bran) and germ from the inner endosperm, which is the starchy part used to make flour. The extraction rate is a measure of how much of the original grain remains in the flour after this process.

For example, if the extraction rate is 70%, it means that 70% of the original grain is included in the flour, and the remaining 30% is discarded as bran and germ. Different extraction rates result in flours with varying levels of nutrients and fiber. High-extraction flours, such as whole wheat flour, retain more of the grain’s components, while low-extraction flours, like white flour, have a higher percentage of the endosperm and fewer nutrients from the bran and germ.