Rye Grain

Rye grain is longer, narrower, and greener-grey than wheat, and it behaves differently in the bakery because of what it contains rather than how it looks. Rye proteins do not form a gluten network in the way wheat proteins do; instead rye doughs are structured largely by pentosans, water-binding carbohydrates that give rye breads their dense crumb and long keeping. This is why rye flour is not a substitute for wheat flour and why rye bread is made by sourdough acidification rather than by conventional straight dough methods.

Alpha-amylase breaks starch down. In a grain that has begun to germinate in the ear — which rye does readily under wet conditions near harvest — enzyme activity rises and the starch in the resulting flour is degraded during baking, giving a sticky, collapsed crumb. The falling number test measures the viscosity of a heated flour slurry and so indexes that activity; low results mean high enzyme activity and unsuitability for breadmaking.

Because rye tolerates far less enzyme activity than wheat before its baking performance fails, falling number functions as the practical gate on the milling market. A lot below the miller requirement is not spoiled — it is feed or distilling grain, where enzyme activity is irrelevant or even useful. The threshold itself is a contract and standard matter and varies by market and product.

Ergot is the overwintering body of the fungus Claviceps purpurea, which replaces a developing grain in the ear with a hard, dark sclerotium. Rye, being cross-pollinated with open florets, is the cereal most exposed to infection, and the sclerotia are harvested along with the grain. They contain alkaloids that are toxic to humans and livestock — historically the cause of ergotism — and they are regulated accordingly in both food and feed.

From a commodity standpoint ergot is a contaminant of the harvested lot, not a crop disease to be managed at this stage. It is addressed by cleaning: sclerotia differ from grain in size, shape, density, and colour, so gravity separation, indented cylinders, and optical sorting can reduce their number. Limits, sampling rules, and whether alkaloid content or sclerotia count is measured all depend on the jurisdiction and the applicable regulation.

Rye is dried and stored much as other cereals are: to a moisture appropriate to the holding period, then kept cool, aerated, and monitored. The distinctive handling requirement is cleaning. Because ergot removal and the separation of light, thin, and foreign material both happen before the grain is stored or shipped, cleaning equipment is closer to the centre of a rye chain than of a wheat chain, and the screenings it takes off must themselves be managed rather than casually fed.

Rye moves in bulk by truck, rail, and vessel, and is segregated by intended market since the milling and feed routes have different requirements and prices.