As It Happens

This chemist cooked up medieval gunpowder recipes and fired them out of a cannon

Chemistry professor Dawn Riegner had a literal blast during her pandemic downtime, as she recreated gunpowder recipes and helped a friend studying medieval weapons.

Medieval gunners modified their gunpowder recipes to be less powerful and safer to transport, study says

From left, Dawn Riegner, her daughter Kathleen Riegner and Tessy Ritchie used their expertise in chemistry to test the medieval gunpowder recipes. (Submitted by Dawn Riegner)

Story Transcript

Chemistry professor Dawn Riegner had a literal blast during her pandemic downtime, as she recreated gunpowder recipes and helped a friend studying medieval weapons.

At the U.S. Military Academy in West Point, N.Y., Riegner usually looks into finding ways of detecting explosives. But over in the history department, her colleague Clifford Rogers had some questions about the various medieval gunpowder recipes he came across in historical records — and why the gunners changed them so often.

"He asked me … 'Do you think this is something we can look at using chemistry?' And I said, 'Let's do it! Let's test all of them,'" Riegner told As It Happens host Carol Off.

They went on to recreate the gunpowder mixtures and launched them from a replica of a medieval cannon. They published their findings this summer in Omega, a peer-reviewed journal of the American Chemical Society.

Get out there and fire a cannon. It is the best thing when you have time on your hands."​​​​​​- Dawn Riegner, chemistry professor

Along with other chemists and historians at the academy, they began their research in early 2020, during the first wave of the COVID-19 pandemic. Riegner also brought her daughter, who is currently a chemical engineering student in Hoboken, N.J., into the mix. 

While the rest of the team socially distanced, the mother and daughter worked side-by-side in a West Point laboratory, carefully measuring the ingredients and cooking up 23 different gunpowder recipes.

Each of the recipes from the medieval gunners between 1338 and 1460 had its own ratio of the base ingredients: sulphur, carbon and potassium nitrate (also known as saltpeter). The gunners likely used charcoal for the first two elements and added saltpeter to it, which can quickly ignite an explosive combustion, Riegner said.

Some recipes also used unusual ingredients, including brandy, varnish and vinegar.

"We wanted to know, did they add these things to increase the amount of energy? Or was it some other reason?" Riegner explained.

A team of chemists and historians recreated 23 different gunpowder recipes from the medieval time period and tested their power. (Submitted by Dawn Riegner)

Once the team of chemists and historians prepared their concoctions, a lieutenant from the military college helped them take all that gunpowder onto the firing range. Using a diagram, he enlisted a foundry to recreate a medieval cannon.

Then, on a sunny day in June 2020, the experts lined up in their flak jackets and helmets — along with medics nearby — at the academy's world-class firing range.

"It's very exciting ... and you can feel it in your gut. It's one of those kind of adventures," Riegner said.

"The cannon fired just beautifully."

What they saw in the explosions that day revealed the true intentions behind the medieval gunners' work. 

In June 2020, experts positioned a replica of a medieval cannon to test gunpowder recipes at the U.S. Military Academy at West Point, N.Y. (Submitted by Dawn Riegner)

They found that the most powerful ratio for gunpowder had three times less sulphur than saltpeter. But the more powerful it was, the more dangerous it became for them to handle and transport for use in their weapons.

"They had to tweak their ratios," Riegner said. "They honed in on a particular ratio and it was able to still give them pretty good power, but they had to use the most expensive ingredient, which was not the brandy ... [but] the saltpeter."

As for whether the team of researchers used the leftover (centuries-old) brandy to toast their findings, Riegner said that just like "any chemical that we bring in the lab, once it's opened ... it's non-edible, it's non-drinkable."

The chemist also said that the only benefit of COVID, to her, was the opportunity to do this kind of research.

"Get out there and fire a cannon. It is the best thing when you have time on your hands."

Written by Mehek Mazhar. Interview with Dawn Riegner produced by Lisa Bryn Rundle.

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