Rye, Secale cereale

Rye was a dangerous plant in medieval Europe. The infestation of ergot led to mass poisoning, especially in times of famine. Today, rye is a popular bread grain, which is particularly popular for its taste and long shelf life.

Deep-reaching roots loosen the soil

The rye plant is an annual and is sown either in the fall or spring to be harvested the following summer. As soon as the grain is in the ground and germinates, several stalks grow, which can be up to 3 meters high. Thanks to targeted breeding for shorter stalks, today’s rye is usually between 1 and 1.5 m high. The roots also have great growth potential and can penetrate a meter deep into the soil. If you look at a rye field, you will notice that the plants have a slightly bluish color. The ears at the tips of the stalks are between 5 and 20 cm long and contain the rye grains. The typical awns, long thin projections resembling bristles, are found on the ears. These have important functions: In nature, awns help to spread the seeds. If an animal grazes a plant, the awns get caught on the animals together with the seeds and end up in other places. The awns also make the plants more drought-tolerant and less popular with predators such as wild boar. However, they can cause problems for humans during harvesting and processing, as they can cause technical problems during threshing and cleaning and wear and tear on harvesting machines.

Rye – a resilient cereal

The wild species of rye, like other important cereals such as wheat and barley, originates from the Fertile Crescent. In cultivation there, rye was probably a ‘weed’ and was carried along with the seeds of other cereals on the way to Europe. Rye was only cultivated in the harsh climate of Europe around 3,500 years ago. Rye is therefore much younger than wheat or barley, which have been cultivated for over 10,000 years. For the Greeks, who lived around 2,000 years ago, rye was only used as food in emergencies, while in colder regions of Europe it was an important bread grain for the Celts, Germanic tribes and Slavs.

In contrast to other cereals, rye has the great advantage of requiring little space: rye also thrives on sandy, nutrient-poor soils with low moisture levels. Winter rye is usually sown in Europe in early fall, as the young plants can withstand temperatures as low as -25°C, making it the most winter-hardy cereal in the world. The following spring, the plant develops quickly so that it can be harvested relatively early. Rye is therefore best for areas with dry summers. Due to the lower environmental requirements, rye is also less sensitive to pests. Consequently, the use of pesticides and fertilisers is less ‘necessary’. Today, rye is mainly grown in Russia, Poland and Germany.

Baking bread with sourdough

Rye has a long history as a bread grain. It takes around 2^m2 of arable land to make a 1 kg loaf of rye bread. Unlike wheat, rye bread cannot be made with pure yeast; you need the acidity of a sourdough. With sourdough, the dough is fermented with the help of lactic acid bacteria and natural yeasts and carbon dioxide is produced, which loosens the dough. Fermentation improves digestibility, aroma, taste and shelf life. But not only baked goods are made from rye, high-quality vodka is also produced from the fermentation and subsequent distillation of rye grains. Rye also plays an important role in animal husbandry. This is because rye can be used as fodder for animals during its green growth phase. The juicy leaves and stems of rye are particularly rich in fiber and can be a valuable source of feed for ruminants such as cattle and sheep. In addition, rye grains are used as supplementary feed due to their high energy density. Rye is also important ‘fodder’ for the soil: rye in mixed cultivation with vetch, for example, can cover the soil as green manure over the winter and thus protect it from erosion, provide soil life with food and loosen the soil.

Mass poisoning from ergot

One challenge in rye cultivation is the ergot mentioned above. Here, the ergot fungus germinates in the ear instead of a rye grain. The result is a dark-colored surviving form of the fungus that resembles an enlarged black grain. Ergot produces poisonous alkaloids that can be fatal to humans. Paralysis, cramps, hallucinations, fainting and the death of entire limbs were the result. In the past, mass poisoning occurred particularly during times of famine, as the poor population did not have sufficient purified grain available. Today, the risk of poisoning has been virtually eliminated by preventive measures in cultivation, appropriate cleaning of the grain and various tests. Rye still causes health problems for pollen allergy sufferers during its flowering period and is a relevant allergy plant.

Sources

University of Potsdam: From weed to crop. The rye. Link.
Wiesemüller, W. (2005): Current and historical significance of ergot. Link.
SWR: How does sourdough work and what happens in bread? Link.
Medienwerkstatt Wissenskarten: The different cereals – rye. Link.
Hillman (2913): On the Origins of Domestic Rye-Secale Cereale: the Finds from Aceramic Can Hasan III in Turkey. Link.
Zohary, D., Hopf, M., & Weiss, E. (2012). Domestication of Plants in the Old World: The origin and spread of domesticated plants in Southwest Asia, Europe, and the Mediterranean Basin. Oxford University Press.