How rolled oats are made

Oats are steamed before they are flattened, because the bran carries an enzyme that turns them rancid.

stations: 6
things upstream: 1
raw source: 1
step from the ground: 1

The short version

Harvested oats are cleaned, then dehulled to leave the inner seed, called a groat. Steam heats the groats to switch off an enzyme that would turn them rancid. They are then rolled flat between heavy rollers and lightly toasted. Thinner flakes steamed longer become quick oats, and cut groats become steel-cut oats.

Clean the grain

Screens and air remove weed seeds, stones and other foreign material from the harvested oats.

Goes in
Oats
Strip off the hulls

Dehulling removes the inedible outer husk and leaves the bran-covered seed, called a groat.
Steam the groats

Steam softens the groats for quicker cooking and denatures enzymes in the bran that would otherwise make the oats go sour or rancid. That gives them a longer shelf life.
Roll them flat

Heavy rollers squash each groat into a flake. Thick flakes stay whole and are sold as old-fashioned oats. Thinner flakes, steamed more, fragment but absorb water faster and are marketed as quick oats.
Toast to stabilize

A light toasting dries and stabilizes the flakes. Steel-cut oats skip rolling and are chopped by a sharp-bladed machine before any steaming.
Pack the flakes

Flakes are poured into canisters and bags for the shelf.