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Learning lessons from Vegemite and lessons learned from mercury

by Matt Davenport
March 5, 2018 | A version of this story appeared in Volume 96, Issue 10

All the yeast extract fit to print

Credit: J. Food Eng.
It comes from a land down under: He just smiled and made me a Vegemite pyramid.
A 3-D printed Vegemite pyramid on toast.
Credit: J. Food Eng.
It comes from a land down under: He just smiled and made me a Vegemite pyramid.

Marc in het Panhuis decided to run Marmite and Vegemite through his three-dimensional printer for chuckles. At least in part. The materials scientist at the University of Wollongong tells Newscripts he likes to make people laugh, then think.

For the thinking part, he hoped that printing the brown pastes would help open people’s minds to understanding his more serious scientific passions. For example, Panhuis’s team recently designed edible pressure sensors from conductive soft materials. Although neither appeared in the actual sensor, both Marmite and Vegemite—ostensible foodstuffs derived from brewers’ yeast—are ingestible, conductive soft materials.

Panhuis says it’s a lot easier to start a casual conversation by talking about a famous toast topping than what the researchers actually used, materials called ionic-covalent entanglement hydrogels.

Furthermore, he adds, 3-D printing yeast extract is a great outreach activity. In about 30 seconds, he can print a conductive Marmite or Vegemite circuit onto a cracker or slice of bread. “It’s an excellent way of explaining things like bioelectronics and swallowable electronics,” he says.

And the project has given his own team some things to think about. For example, the researchers recently published a rheological study of Marmite and Vegemite, which led them to conclude Vegemite was better for 3-D printing, generally speaking (J. Food Eng. 2017, DOI: 10.1016/j.jfoodeng.2017.01.008). Vegemite is also more conductive than Marmite, but that’s not altogether surprising because Vegemite has more salt and thus more charge carriers, Panhuis says.

What did surprise the Newscripts gang, however, was how Panhuis feels about the yeast extract he prints.

“I can’t stand it,” he says. “I’m a chocolate man.”

Our readers are Hg wells

Credit: Lydia E. Moissides-Hines
Maybe this will jug your memory: Reminiscing about a mercurial past.
A photo shows an old jug used to store mercury.
Credit: Lydia E. Moissides-Hines
Maybe this will jug your memory: Reminiscing about a mercurial past.

Back in December, Newscripts wrote about a jar with 5 kg of mercury that made its way into a bar in Iowa. Since then, we’ve received several stories about our readers’ experiences with the element, and we wanted to share a few here.

Bob Davenport—no relation to this Newscriptster, as far as we know—writes that as an elementary school student in the 1950s, many kids and adults considered mercury a toy. “Kids would show up with small containers of the marvelous element and we would coat our pennies so they glistened like new dimes,” he says, adding that young people today would probably have a hard time believing such a thing was once so common.

Lydia E. Moissides-Hines shared a wonderful photo of a mercury jug from her personal collection. Although she recently downsized because of a move, she was able to donate some chemistry items to a high school in Wisconsin, some to new faculty members at a nearby university, and others to a local glass blower. She still has the jug in the photo, but donated two others to a thrift shop.

And, last, Jim Ling writes that he recently attended a reunion at Cornell University and was talking to a current faculty member about a laboratory that was renovated since Ling’s student days. The lab used to house manometers that would occasionally blow over, spitting out droplets of mercury that students would push around with their lab notebooks until the droplets fell into grates. The faculty member then exclaimed, “That’s why we found so much mercury here when we were renovating the lab! We had to call in the hazmat team before we could proceed.”

Matt Davenport wrote this week’s column. Please send comments and suggestions to


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