How sustainable is afterburner technology in coffee roasting?

Pavel Corena
June 15, 2023
An image of a large-scale coffee roaster, Probat coffee roaster with a coffee roaster loading in green coffee in an article on how sustainable is afterburner technology in coffee roasting

Much like the majority of consumer products, coffee has a carbon footprint attached to its production, transportation, transformation, and consumption. From farm to cup, there are many processes along the coffee supply chain that generate carbon emissions. For instance, recent studies show a single shot of espresso has an average carbon footprint of about 0.28kg

The roasting of coffee tends to produce some of the largest emissions along the supply chain. Roasting coffee contributes around 15% to the industry’s carbon footprint. As a result, coffee roasters are finding ways to reduce their carbon footprint and contribute to a more sustainable industry.

One solution is the use of afterburner technology, which is often implemented across several industries in order to reduce carbon emissions. However, many have questioned whether this technology is as sustainable as it seems. Therefore, roasters should do their research before investing.

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What is an afterburner & why is it used in coffee roasting?

Roasting coffee produces four types of emissions: dust, chaff, odour, and smoke. Dust is often created during the handling of green coffee, while chaff is formed when the silverskins of the beans fall off during the roast. Meanwhile, the smoke and odour produced during a roast are combinations of organic constituents volatised at roasting temperatures and steam produced when the roast is quenched with water.

These fumes consist of several volatile organic compounds (VOCs), including diacetyl, 2,3-pentanedione, and other less harmful chemicals, along with carbon dioxide and carbon monoxide. As well as imparting smokey flavours on the coffee, these fumes pose a risk to those within proximity of the roaster if inhaled. Carbon dioxide also contributes to global warming because it builds up in the atmosphere, which traps heat and causes the temperature of the planet to rise. Ideally, these pollutants should be treated separately away from the coffee drum. 

Essentially, an afterburner oxidises the waste gases from roasting and uses a combustion process to generate “cleaner” emissions. It is an insulated tube with a high-power gas burner. Smoke enters the chamber and is incinerated by the burner, transforming into carbon. Nearly all the VOCs and smoke particles are reduced to carbon, leaving virtually no visible smoke or odour.

Afterburner technology is generally used in coffee roasting to reduce emissions and protect the beans from taking on alternative “flavours”. If the beans are exposed to air pollutants and smoke, they may have smoky-tasting notes that affect the overall quality of the cup.

An image of a coffee roaster collecting roast coffee during a coffee roast using afterburner technology in an article on how sustainable is afterburner technology in coffee roasting

Is afterburner technology in coffee roasting sustainable?

Afterburners can provide roasters with several benefits, such as reducing odours and emissions. Some afterburners may even reduce 90-95% of the visible smoke and odour from a roastery. However, the technology is a controversial topic within the industry, as some wonder if it is entirely effective in reducing the carbon footprint of the roasting process.

From an environmental and sustainability perspective, it may not be as ideal, as it is simply displacing the roaster’s carbon footprint from one point to another. While an afterburner helps roasters reduce smoke, the gas used to run the machine also creates a carbon footprint. Notably, some afterburners may use twice as much gas as the roaster itself.

Beyond that, afterburners may also be susceptible to fires due to the high operating temperatures. Any buildup of coffee oils or chaff poses a serious risk, so, the system around the afterburner needs to be carefully maintained. 

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What alternatives do coffee roasters have?

In light of this, manufacturers are taking action and finding ways to make afterburner technology more sustainable. For example, Vortx Klean Air has released an EcoFilter that claims to clean the air and capture carbon dioxide produced by the roaster – and it is cost-effective.

The brand has developed an alternative filtration system that combines the energy of a high-efficiency cyclone and the power of atomised water to remove pollutants generated by the roasting process. 

Alternatively, roasters can invest in an electrostatic precipitator (ESP). An ESP uses an electrical charge to remove smoke and pollutants from the gas stream produced during a roast. The gas is passed through a series of plates, which are charged with a high voltage. The smoke and pollutants are attracted to the charged plates, where they are collected and removed from the gas stream. The clean gas is then released back into the atmosphere.

While ESPs do not require gas to operate, depending on the size of the roaster, it is likely that one will not be enough. More so, cleaning the plates can be time-consuming and laborious. 

Roaster can also move towards becoming carbon neutral by focusing on other aspects of the business, such as the packaging process. Investing in biodegradable, compostable, or recyclable coffee packaging and takeaway cups can be one of the most effective ways to improve sustainability credentials. At MTPak Coffee, we are aware of the need for coffee roasters to find sustainable solutions. We offer a range of 100% recyclable coffee packaging options made from renewable materials such as kraft paper, rice paper, or multilayer LDPE packaging with an environmentally friendly PLA lining, all of which minimise waste and contribute to a circular economy. 

We also offer recyclable degassing valves and resealable zippers, while all our inks are water-based and low in volatile organic compounds (VOCs). Our kraft paper bags and takeaway cups are FSC-certified, while our compostable options are certified compostable by TÜV Austria.

Our design team is readily available to help you create the ideal coffee packaging that reflects your commitment to sustainability. Plus, we are able to custom-print coffee bags using innovative digital printing technology, with a quick turnaround time. We offer a wide range of customisation techniques, including spot UV with a glossy, satin, or matte finish, embossing and debossing, as well as hot foil stamping in a variety of colours, to name a few. 

MTPak Coffee also offers low minimum order quantities (MOQs) to micro-roasters who are looking to remain agile while showcasing brand identity and a commitment to the environment.

For more information on sustainable, custom-printed coffee packaging, contact our team. 

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