Roller milling is the dominant industrial grain-milling process, using sequential pairs of corrugated and smooth steel rollers to break open the grain and progressively reduce the endosperm into flour of consistent quality.
In trade practice
Mill operators set roller gaps and speeds to control particle size and extraction rate, with each pass separating bran, germ and endosperm fractions. Buyers specify flour parameters such as ash content, protein level and falling number, all of which reflect roller-milling settings and incoming grain quality. A common sourcing error is conflating roller-milled flour with stone-milled flour, which differ in bran particle distribution and shelf life. Quality certificates from accredited laboratories confirm that the finished flour meets contracted specifications.
In a specification
A flour supply contract typically references extraction rate and ash content as measurable outputs of the roller-milling process, with testing method and frequency stated alongside tolerance limits.