Greg Scace talks coffee science for Knowledge Talks

The creator of the Scace Device, Greg Scace, has captivated audiences in Sydney and Melbourne as the guest speaker in Toby’s Estate Knowledge Talks.

Greg made the journey from Washington DC, United States to Sydney to star in the his first Knowledge Talks session at Toby’s Estate Chippendale Cafe on 17 February, followed by a second performance at Toby’s Estate’s Flinders Street cafe on 18 February.

An engineer by profession at the National Institute of Standards and Technology in the United States, Greg presented a talk on the current state of espresso extraction, titled: “Hey’ll, what happens if you push this button?”

Greg, who identifies himself as a “measurements geek”, gave attendees a chemistry lesson into the properties and compounds of coffee, its solubility, concentration gradients, heat reservoirs, conduction heat transfer, and factors controlling surface area such as coffee dose, grinder adjustment and particle size and shape.

“Maths can be scary, science is really cool, and when you apply it to coffee, it’s just plain fun,” Greg said. “I believe that things happen in a fundamental way. There are laws of motion, mechanics and engineering and that doesn’t change just because we’re talking about coffee. If you can understand how and why things apply to coffee in general, then you can apply those theories to all kinds of coffee such as filter and espresso.

Greg went on to talk about extraction mechanics, conditions of extraction, its impact on coffee, and tools being used to help increase coffee quality and provide consistency.

“It’s important to understand that the surface area of coffee particles, particle geometry, uniformity and control have a huge influence on extraction rate. But we can’t control extraction without controlling temperature of the coffee, surface area, and surrounding water. Water flow around coffee particles must be controlled and reproducible,” he said.

Greg’s discussion proved popular with both Sydney and Melbourne audiences, who were invited to delve deeper into the theories of applied coffee science to better understand espresso extraction.

“The main conclusions we can draw about the temperature and the flow of heat in coffee is that energy moves from water to coffee during extraction, which results in temperature change in both. The rate of temperature change however, is dependent on depth within the coffee cake, so to speak – the top moves more quickly than the bottom. Diffusivity coefficient is greatest at the top of the coffee cake, but extraction rate is fastest at the bottom.”

While Greg admits his session appeals to the “inner coffee geeks”, those without a science or technical background could still take away some valuable lessons.

“I hope through this discussion of extraction and engineering principles I have successfully communicated how espresso extraction works, why various factors are important, and emphasised that processes are time and spaciously dependent and not constant,” he said.

“The exciting thing is that we have tools to be reproducible and do things right, but we always need to ask ourselves why things happen, and why we do things in a certain way. We have to remember that a guy with a bit of foresight, tinkering away in a kitchen, can change the industry. And those with ability and curiosity to try can blow the industry apart and do something interesting, and then people will pay attention. It’s really cool.”

This was Greg’s first visit to Australia. In addition to starring in the Knowledge Talks series, Greg says he was keen to explore Melbourne and Sydney’s coffee scene, and experience some Australian wildlife. “I’m so happy to be here – I’m just wary of funnel web spiders and the box jelly fish up north,” he said. “But I’m already impressed, in the short amount of time I’ve been I can see a really sophisticated culture and great curiosity from baristas. It’s that curiosity that has the power to  influence the entire industry.”

Toby’s Estates Managing Director Cosimo Libardo says inviting industry icons such as Greg to the country is about bringing real education to the Australian coffee scene.

“It’s an honour to have Greg speak to Australian audiences who are demanding a heightened knowledge of technical education. There’s definitely a stronger need for education in this industry, and the Knowledge Talks session are really a valuable platform to share information. If anyone can make science interesting its Greg, and I think we saw that tonight,” said Cosimo.

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