Maize grits -- Satisfying the brewer

by Emily Buckley
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One World Grain reader revisits the fundamentals of grit milling, through the heartaches and resulting pride

Grit milling can be very tasking or even frustrating work, especially when its process is not patiently and scientifically followed. On the other hand, any maize miller’s face beams with joy of satisfaction when the correct grit that will meet the brewer’s specification is dropped at the packaging point. For this to happen, the milling operation must be carefully followed right from the outset, through each intermediary pathway until the last.

To start, preparation of maize for milling is the first crucial step; and once a mistake is made here, no matter the experience of the miller, doom looms.

Maize preparation involves the introduction of water followed by a conditioning period. The dampening system used should be the type that allows for a controlled moisture release to the stock and ensures a uniform distribution throughout the grain.

There are two sides to the coin in stock moisture level. While excess water hampers easy flow of material along the production line, low or insufficient moisture means brittle stock such that bran and germ are not easily discarded from the endosperm — in fact, bran powder is largely formed.

The accuracy of an oven test is required to determine the moisture level, even though it takes longer than electronic testing. Water addition makes up for the inevitable moisture loss in the milling process through grinding heat and conveying (especially the pneumatic type due to air drying). In all, the brewer prefers the grit’s moisture level not to exceed 13%.

With optimum milling moisture, the degerminator will hardly have a problem in its work. And if the degermer knocks off the germ effectively from the endosperm, the densimetric table or separator will easily make a clear distinction between the lighter germ and bran and the weightier endosperm.

Also, as a result of good moisture, the roller mill will easily deliver bran-free grit for the purifier to sieve. With this situation, the miller only needs a good sieve arrangement and an effective aspiration system to be happy with the final product.

Further, the brewer does not want his grit to be ridden with unwanted foreign particles or infestation. At the same time, the brewer will frown at rancid or moldy grits. He wants a clean odor, and as much as possible, a uniformly colored product.

Sieve Analysis

A typical brewer has a maize grit sieve analysis table that looks thus:

Sieve No.

Normal Throughput %






50 to 60


35 to 45





It of course follows that the more you deviate from the brewer’s norm, the more the chance of your consignment being rejected.


Principally, among all the control points that the brewer watches out for, none draws his bile more than a high level of fat. Though grains comprise about 3% lipid, the brewer expects your grit’s fat content not to exceed 0.8%.

And major culprits contributing to high fat levels are germ and bran contamination in grit. Therefore, a miller will always endeavor to see that these factors are controlled at every stage of production. If you satisfy the brewer, you will find grit milling to be an enjoyable enterprise. Good luck!


Ubani Ariba is a miller with Continental Industries (W.A.) Ltd., located in Aba,

Abia State, Nigeria. "I am making this little contribution, as a token of my appreciation for your [magazine]," he said. He can be reached at

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