Durum Wheat Grain

Durum is the hardest of the cultivated wheats. Its endosperm is dense and glassy — described in the trade as vitreous — and characteristically amber in colour. That structure is what makes durum suitable for semolina milling: the endosperm fractures into coarse, angular particles rather than crushing to fine flour, and those particles are what pasta extrusion requires.

Durum milling is run to produce semolina. The mill grinds and sifts to recover coarse endosperm particles of a controlled size; the finer flour that is unavoidably produced alongside them leaves as durum flour, a genuine co-product with its own markets in couscous, some flatbreads, and noodle products. Lots that fail semolina requirements — too starchy, too weathered, or off-colour — are commonly diverted to feed, and a portion of the crop is retained as seed.

• Food — semolina for dried pasta, fresh pasta, and couscous
• Food — durum flour for regional breads and noodle products
• Feed — lots that do not meet semolina milling requirements
• Seed — retained or certified for the next planting

Durum is graded on the attributes common to all cereal grains — moisture, test weight, soundness, foreign material — plus attributes specific to its end use. The proportion of hard vitreous kernels is the defining one: national standards subdivide the durum class by vitreous kernel count and amber colour, because starchy kernels mill poorly into semolina. Protein content and yellow pigment concentration are also priced, since they drive pasta firmness and colour respectively.

The relevant defects are those that destroy vitreousness or stain the endosperm. Piebald or yellow-berry kernels are partly starchy and downgrade a lot; black point discolours the germ end and carries through into semolina specks; sprout damage raises enzyme activity and weakens the cooked product. As with any grain, the applicable thresholds live in the standard in force in the selling jurisdiction, not in a general reference.

Durum stores like other hard wheats: it is hygroscopic and respires, so it must be dried to a moisture appropriate to the intended holding period and then kept cool, aerated, and monitored. Two commodity-specific points matter. Colour is a saleable attribute, and prolonged weathering or heating dulls it. And because durum and common wheat look broadly similar in bulk yet command different prices, segregation and lot identity through the handling chain are commercially critical — admixture with bread wheat is itself a grading defect.