How flour became white, and what that cost

Stone milling crushes the whole grain between surfaces and then sieves out what is not wanted. The germ is crushed along with everything else, so its oil is distributed through the flour; separating bran and germ completely is difficult, and a white flour produced this way is expensive because so much is discarded to get it.

Roller milling breaks the grain open between fluted rollers and separates the parts before grinding them. Bran and germ can be removed cleanly and the starchy endosperm milled on its own. White flour stops being a luxury.

That is the whole of the technical difference, and almost everything else follows from it.

The germ contains oil, and oil goes rancid. Wholemeal flour therefore has a genuinely shorter shelf life than white, and this is not a marketing claim — it is the reason white flour could be milled centrally, transported and stored in a way wholemeal could not.

Removing the bran does something different and equally consequential. Bran binds water strongly, competing with the gluten network for it, which is why wholemeal doughs behave as though they are drier than their hydration suggests. A white flour has none of that competition, so it forms a stronger network more easily and makes a lighter loaf with less skill.

BakeHQ states this without a value judgement in either direction. What roller milling produced was a flour that keeps, travels and bakes easily; what it removed was fibre, some micronutrients and a certain amount of flavour.

Several countries require certain nutrients to be added back to white flour by law. That requirement exists because the milling process removes them, and it is the clearest institutional acknowledgement that the change had a cost worth legislating about.

BakeHQ notes the existence of fortification because it explains why a bag of plain flour lists added ingredients, and stops there. Which nutrients are required, at what levels and in which countries is a regulatory question that changes, and nutrition is outside this site’s editorial scope.