The Milling Process
All of the milling machinery remains in place at the Stockdale Mill.
The milling process involves wheat receiving, wheat preperation, grinding,
sifting, and packaging.
Products produced are: flour, wheatgerm, middlings, and bran.
Wheat was received at the Stockdale Mill in the weigh shed on the north end of the mill. If brought in bulk in a farmer's wagon, the wagon was weighed on the large scales. A hand winch raised the front of the wagon and the wheat was dumped into a bin below the driveway floor. The wagon then was weighed empty to determine the load weight. If the wheat was brought in in bags, the bagged wheat was weighed on the floor scales and dumped into a bin via a trapdoor. The mill used "soft winter" wheat. The farmer was either paid for the wheat at market price, or the miller "exchanged" the wheat at 30 pounds of flour for each bushel (60 pounds) of wheat.
Nordyke & Marmon, Indianapolis,
- click to view -
Wheat first passes though a 'fanning mill'. The fan blows off the chaff. Screens seperate straws from the wheat, and finer screens seperate kernels of wheat too small for processing (and broken kerenels). The wheat then is stored in a bin until needed.
When wheat is needed for milling, it is brought from the holding bin into further wheat preperation. A 'scouring machine' knocks off the thin fuzzy outer layer of the grain. The wheat then proceeds to a 'tempering' bin. The wheat is held in this special bin for several days (conditioning) until the moisture content is right for milling (around 16%). When conditioned, the wheat is again scoured, then sent to the milling hopper.
The earlier grinding stones (buhrs) were replaced at the Stockdale Mill with 'roller mills'. In roller mill technology the wheat passes between two steel rollers which are each 6 inches in diameter. The rollers spin towards each other at high speed. Each roller spins at a different speed and its surface is grooved with a different textrure than the other roller. The rollers are set with a specified opening width between them.
The rollers grab the grain and pulled it in, crushing it in the process. (one set of rollers are also called a 'break') Additonal breaks would be set for finer grinds as the material continues through the processing. The full process requires 4 roller mills containing 8 sets of breaks.
There are two basic types of sifters (also called 'seperators').
"Sieve" sifters use flat trays with a screen or silk fabric on the bottom of the tray. The trays are rocked to move material through. Material enters on end of the tray, finer material that passes though the screen or fabric is directed to one process and courser material that continues to the other end is sent to different process. The Stockdale Mill has a large sifter with 64 trays.
"Bolt" sifters are horizontal cylinders with a screen or silk fabric lining the cylinder. Material enters the interior of the cylinder at on end. The cylinder rotates and vibrates to move material through. The bolt separates the material that passes though the screen or fabric from the material that continues out the far end. The Stockdale Mill has 3 bolt sifters.
An array of spouts (or 'chutes") direct sifted material to the next process
for that 'grade' of material.
First sifted out is bran (yes, the same bran that you had for breakfast). Stockdale Mill bran was bagged in cloth bags and sold for animal feed.
Next to sift out is middlings. (also called 'midds' or 'shorts') Middlings were also bagged and sold for animal feed. Middlings have a courser texture than flour; some of the country's large mills will grind and bleach the middlings and add it back to the flour.
Also sifted out is the wheatgerm. This healthy product is high in vitamin-E and is used as a breakfast cereal. Only a small amount of wheatgerm is produced.
What remains after removing bran, middlings, and wheatgerm: pure white flour. "White Loaf" flour had to pass though a final bolting using the finest silk.
"White Loaf" flour was packaged in paper bags in 5 pound, 10 pound, and 25 pound sizes. A special 'packing machine' was used to fill the bags. Each bag was checked for the proper weight, then hand crimped and hand tied. Packaged four was exchanged for wheat, sold directly to walk-in customers, or sold wholesale to stores and bakerys.
Bran is light and fluffy. Fifty pounds would fit into a burlap bag if filled from a spout. A special 'bran packer' would pack 100 pounds into a bag.
Middlings was packaged in cotton feed bags, each holding from 80 to 100 pounds.
Wheatgerm was packaged into paper bags by a hand-scoup at the mill.
<<< BACK to Structure