Through the Mill

So, what can you do with a whole wheat berry? Well, you can eat it as it is, though that’s a chewing-intensive experience that frequently results in indigestion. You can cook it then eat it, which can be a very nice experience indeed. Or, if you want to greatly expand the possible culinary uses of the berry, you can mill it into flour.

Flour milling, as I’ve mentioned in previous posts, is very different from corn milling. It’s much more involved. While corn can simply be crushed to powder between stones and stored, oily wheat berries must be separated into their component parts first, at least if the finished flour is going to have any keeping ability. A fairly elaborate configuration of rollers and sifters is required.

The process of wheat milling starts by separating out all non-wheat particles like bits of stalk and stones. The wheat berries are then scoured to remove husks and dirt. Next they’re “tempered”, which is to say moistened and briefy stored to harden the outer bran and soften the inner endosperm, to make the separation porcess easier.

Milling begins by passing the berries through corrugated iron rollers, the so-called “first break”, which crushes the berries into what are called “middlings”. The wheat is then passed through a sifter, which separates the middlings into different sizes. Each size goes into its own purifier, where air currents lift off and carry away the bits of shattered bran. From there the various sizes of middlings are passed through their own sets of steel “reducing rollers” which pinch off the germ and crush the pieces of endosperm into flour. The whole mess is then put through another multi-layered sifter. Pieces that don’t make it to the bottom of the sifter as finished flour are re-purified and re-rolled until they’re fine enough.

At this point the flour is often “bleached”, which means exposed to either chlorine gas or benzoyl peroxide. This whitens the flour, but contrary to popular belief doesn’t leave any chemical residues behind, nor does it destroy any nutrients. It does however have an effect on gluten, but that’s something I’ve already discussed in posts like this. The last step is enrichment, where the various B vitamins, thiamine, niacon, riboflavin, and (ever since 1998) folic acid are re-introduced.

And that’s how the wheat berry crumbles, at least when it comes to making conventional white flour. The process for making whole wheat flour has a few extra steps. But more on that tomorrow.