March 18, 2021

Exploring the environmental impact of coffee roasting

There are over 2,000 coffee roasting businesses in the US alone. Many of them are conscious of the growing consumer focus on sustainability, both in terms of the coffee supply chain and the environment. 

And despite an increasing sector-wide focus on sourcing ethical, organic, and eco-friendly coffee, the environmental impact of other parts of the supply chain can sometimes be overlooked. This includes coffee roasting itself.

However, in the last few years, there has been a move towards better energy efficiency and more sustainable technology in roasters. To learn more about this, I spoke to Dennis Vogel from Loring, and Ram Evgi from Coffee-Tech Engineering. Read on to find out what they told me.

You might also like our article on improving sustainability in the roastery.

What are the environmental issues for roasters?

There are a number of environmental concerns about coffee roasting. Along with the carbon emissions and other hazardous gases released as a byproduct of the fuel combustion in the roaster, coffee roasting also generates smoke and other harmful particulates. These emissions can be dangerous for those operating or working near the roaster, as well as contributing to greenhouse gas pollution.

Ram Evgi is the CEO and founder of Coffee-Tech Engineering, based in Israel. “The damage to the environment is caused by what we pull out of the duct,” he tells me. 

“However, the more immediate damage can happen to the roastmaster themselves, and anything in the surrounding area that is exposed.”

Across the coffee sector, brands like Coffee-Tech Engineering and roaster manufacturers have been monitoring the levels of these emissions for some time. Dennis Vogel is the Director of Marketing and Sales at Loring, a roaster manufacturer headquartered in California.

Dennis says: “Traditional roasters produce visible emissions (i.e. smoke), odours, and pollutants such as nitrogen oxide, carbon monoxide, volatile organic compounds, and carbon dioxide, unless a filtering system or external afterburner is used.

“In addition, afterburners also consume fuel, which is traditionally natural gas or liquefied petroleum gas (typically propane).”

What causes these issues?

To put it simply, there is something of a “lag time” when it comes to innovation in roaster technology. Moving through processes like design, proof of concept, and manufacture to distribution and widespread use can take years.

Many specialty coffee roasters started out using (and still use) machines that were originally designed in the mid-20th century. Many of these original machines have since been refurbished, upgraded, or even re-released to meet new demands for quality, consistency, batch size, and aesthetic quality. 

However, at the time when these machines were initially designed, climate change and biodiversity were arguably not that high on the global agenda. As such, emissions regulations would have been much more relaxed, and the environmental impact of the roaster would not have been a priority.

Ram also says that there are certain structural “design flaws“ that are responsible for most of the environmental concerns in coffee roasting.

“An important issue which is regularly overlooked is the structure of the machine itself,” he says. “This is related to many different aspects, including user safety, efficiency, repeatability, and accuracy.

“Most machines up to 100kg batch capacity still utilise open-structure atmospheric drum housing. This means that the burner is operating within the same atmosphere as the room, aspirating (drawing in) the preliminary air by itself, rather than in a sealed structure with sub-atmospheric conditions.

“This effectively means that every emission coming out of the burner is also spread into the roasting space.”

In comparison, Ram says that contemporary “greener” roasters (such as those used by Coffee-Tech Engineering) can isolate these emissions within the machine. This protects the environment around the roaster (including the operator) and gives the machine more time to break down these harmful gases. This effectively “cleans” the emissions.

This isolation process also has the secondary benefit of absorbing the thermal energy in the emitted air to keep the machine heated. This improves energy efficiency for continuous roasting, making the roaster even more sustainable.

Can you “fix” your roaster?

Most roasters are trained on a certain model or machine through years of practice. Each roaster is different, and changing models can render your finely-tweaked pre-recorded roast profiles useless if they don’t translate properly to a shiny new machine.

Furthermore, roasters generally represent a significant capital outlay for small and medium businesses. A good commercial roaster can be difficult to find for anything under US $10,000. For those looking at cutting-edge environmentally-friendly roasting tech, it’s likely to be much more costly.

As such, for many roasters, the first port of call is fixing an existing machine, rather than buying a new one. Despite this, Ram says that converting your roaster to make it more “green” is easier said than done, especially for older models.

“It’s not always worth the effort,” Ram explains. “Most traditional machines use open atmospheric drum housing (which releases the emissions into the room, as mentioned previously) and no real combustion chamber. This means it will keep on sharing anything happening inside the machine with the room it sits in.

“The burner can be upgraded or changed, as with many other parts, but the quality of the machine is not so much down to the accessories. It lies more in its initial design, and in its organic structure.”

Ram uses the analogy of buying a new car to explain his point: “Adding anti-lock braking or modern tyres will help, but there is nothing better than modern suspension geometry and optimal weight distribution.”

A new generation of roasters

In today’s sector, the environmental impact of the coffee supply chain is rightly becoming a more prominent issue. Forbes research shows that consumers are more likely to be loyal to sustainable brands. As such, roasters who make a commitment to sustainability are more likely to see brand loyalty from both retail and wholesale customers.

This has sparked a movement towards the design and manufacture of several energy-efficient or “green” roasters over the past few years. However, the technology used in these newer designs isn’t necessarily new or revolutionary; the way it is being used is where the innovation lies.

Dennis tells me that Loring has recognised this challenge from customer feedback. “The feedback we’ve received from our customers consistently indicates that environmental sustainability and air quality are among the top challenges they face,” he says. “Our customers value environmental responsibility too, meaning that lower emissions and fossil fuel consumption lead them to select our roasters.”

He says that there’s a specific design Loring has used to create a more environmentally-friendly machine.

“Our roasters utilise a single burner to both roast coffee and incinerate the smoke created during the roasting process,” he says. “This essentially eliminates the need for an external afterburner.

“In addition, by recirculating the air through our closed-loop system, less energy is required to heat the already-warm air to ideal roasting temperatures, while traditional systems must use more energy to [do so].”

However, even though newer models are becoming more prominent, Ram says the benefits aren’t as high a priority for roasters as some might think. He also says that the figures aren’t always precise, meaning that it can be difficult to get customers to acknowledge the financial benefit of a more energy-efficient roaster.

“It isn’t simple to predict gas consumptions from the brochure, and not easy at all to measure them,” he says. “Additionally, while some machines are smoke-free thanks to their internal gas recirculation system, this is not a new development. It was invented by Vittoria [as early as] the 1980s, and has been adopted by few other companies [since then].”

While traditional roasters can be upgraded to become more energy-efficient, it seems like the full structure of older models is more of an issue than particular components or features. Add to that the fact that roasters are significant investments for any individual or business, and it becomes clear that the choice to use a “green” roaster isn’t always a simple one.

In spite of this, the number of energy-efficient roasters emerging on the market is a step in the right direction. The lag time and the investment required means we may only see the benefits of this switch in the long term, but the innovation is there. While it’s not going to happen overnight, greener coffee roasting is a possibility – and it can save roasters money while shrinking their carbon footprint.

Enjoyed this? Then read our article on how you can consume coffee in a more environmentally responsible way.

Perfect Daily Grind

Photo credits: Coffee-Tech Engineering

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