Ancient food wisdom for modern food security

What did the patron saints of Ireland eat? From what we can tell, Patrick, Columba, Brigid and their peers could have chowed down on a variety of locally-grown foods, including rye, peas, barley, oats and different wheat varieties.

And while it’s fun to imagine it, there’s a pressing reason to know the details. Researchers believe that getting a better understanding of ancient foods could help protect our food security into the future.

In particular, ancient grains and legumes could boost the variety, resilience and local adaptations of crops grown in Ireland, while fermented foods can lead to health benefits, extended shelf lives and reduced waste.

Diversity need

Lack of genetic diversity among the crops that nourish us is a potential threat to our food security. That’s according to University College Dublin researchers Dr Meriel McClatchie and Dr Sónia Negrão who started their collaboration in UCD Earth Institute. Today they are combining their expertise in plant science and archaeology to come up with solutions to protect our future food supply.

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“In the last century or two, we have seen a huge loss of diversity and a genetic erosion in the crops that supply our food,” says Negrão, an assistant professor in UCD School of Biology and Environmental Science. “This means we rely largely on limited varieties of crops, such as wheat and barley and rice, grown at scale.”

But banking our future on a narrow diversity of crop varieties is a risky strategy, she says. “We are living in a time of climate extremes, changing weather patterns and environmental degradation, and a narrow genetic base in our grain supply increases the risk of crops growing poorly and being damaged by disease or weather events.”

More diversity offers the potential for crops that are more tolerant to stresses like floods and droughts, and that can fend off infections and pests, Negrão says.

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She and archaeologist McClatchie have teamed up to map ancient grains in Ireland over the past 6,000 years or so. Their Irish Research Council-funded Croprevive project focuses on data for rye, peas and emmer wheat, and consults with farmers to find out why these crops are underused today.

“We want to encourage people to reconnect with these ancient crops, grow them again where it suits, and boost crop diversity and nutrition,” says McClatchie, an associate professor at UCD School of Archaeology.

Rye solution

To map what grew where and when in Ireland, they are poring over thousands of excavation reports and historical records and analysing modern data sets. Archaeological evidence can tell us what people in Ireland ate going back as far as 10,000 years ago, according to McClatchie, who leads the Croprevive project.

“From the introduction of farming about 6,000 years ago people grew quite a wide variety of foods in Ireland. Then about 3,500 years ago, in the Bronze Age, we see a big increase in the production of cereals – including emmer wheat – and this contributed to wealth and stability, people could store and trade surpluses,” she says.

Fast forward to medieval times, and saints and Vikings would have had access to a variety of crops, including rye, bread and emmer wheat, spelt, fruits, vegetables, legumes, nuts and the relative newcomer oats, McClatchie adds. “Historical legal texts from the seventh and eighth centuries list bread wheat and rye as high-status crops,” she says. “And while rye was not the main crop for any period in the past, it would have been grown across a wide spread of the island. But then in recent centuries we see rye drop off.”

Peas, too, have fallen out of favour as a crop for human food in Ireland, and Negrão believes a smart approach that matches varieties to local conditions could put them back on the map.

“Rainfall patterns in Ireland are changing, which can make it challenging to harvest peas,” she says. “But varieties of peas that have a shorter growth cycle and that do not grow as tall could be well adapted to the changing Irish weather patterns.”

Ancient plants

Plant remains have long been something of a poor cousin in food archaeology, according to McClatchie, but they are coming increasingly into focus.

“Animal bones tend to remain preserved at a site for a long time, and they can tell us about meat and dairy products, which people in Ireland ate,” she says. “The bones are quite easy to recover during an excavation. But it takes a few more stages to recover the plant remains.”

Those plant remains tend to survive well in acidic bogs, waterlogged sites and where they have been charred in fire, and finding them starts with identifying the likely spots for food clues.

“We zone in on different activity areas, such as an indoor hearth, a storage pit, outdoor toilet pits, and we gather about 10 or 20 litres of soil from each of these areas, then bring them back to the lab,” McClatchie says.

“Most often, plant remains survive because they were burnt. For this material, we put water into the soil in buckets and agitate that solution with our hands. That allows the charred remains to float to the top, then we sieve them out and identify them under the microscope using modern specimens, guides and pictures. Some of them are wrecked, but often you can distinguish what the type of nut or seed or cereal it was, and maybe even the more specific variety. It would be a rare archaeological excavation where you would learn nothing about the plant remains.”

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Sustainable storage

McClatchie believes we can also learn from how people stored food in eras before electricity and energy-guzzling refrigeration – and she is putting ancient methods to the test.

“In several areas of Europe, underground pits were one way to preserve grains in the past,” she says. “These pits were maybe a metre or two in depth, and very well sealed, for example with clay. The grain around the perimeter would begin to rot, but as the carbon dioxide in the pit rose, the bulk of the grain would have kept well.”

McClatchie worked on experimental pits to store grain during her PhD in England. “When we opened these pits after several months, it was the worst smell I have ever encountered,” she says. “But around 80 per cent of the grain had been preserved.”

As part of the Irish Research Council INSTAR+ funded project, Foodsec, her team has now dug several grain pits in collaboration with farmers in Kilkenny and Meath. Their experiments are showing how oxygen levels fall dramatically as carbon dioxide soars, and the temperature can get to a toasty 30 degrees.

“Initial results from sensors within the pits suggest that the grain becomes slightly fermented, which would have intensified the flavour, and made it even easier to store above ground,” she says. “We plan to open our experimental pits at Cornstown House, Co Meath, around the spring equinox in March, and we are looking forward to seeing if this low-tech method of underground storage is effective in Ireland.”

Fermentation option

Fermentation has been harnessed around the world for thousands of years and is now front and centre of a more sustainable future, according to Prof Paul Cotter, head of food biosciences at Teagasc.

In fermentation, a food or drink is changed through the “desired activity” of microbes, as opposed to undesirable spoilage, he explains, citing examples such as yoghurt, fermented fish, kimchi, kefir and sourdough bread, as well as the long tradition in Ireland of making cheese and buttermilk.

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The microbial activity in fermentation can improve flavour of a food, extend its shelf life and confer health benefits, and Cotter and colleagues at APC Microbiome Ireland; VistaMilk and Food for Health Ireland are researching the impact of fermented foods on the microbes that live in our gut.

To get more fermented foods into our diets, Cotter recommends making your own if possible, supporting local artisanal producers and choosing products in supermarkets that have live microbes and low sugar contents.

Microbes can also help us build a more environmentally friendly future by enabling better use of waste, he adds. “Microbial activity can bioconvert organic waste into fuels and textiles. This is a much more sustainable and valuable outcome than just disposing of it.”

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