Coffee is one of the most important drinks besides water. If every person on earth would drink coffee, statistically they drank 63 cups a year. As there is a great regional difference, let's make it clear with an example: In 2020, statistically every Italian drank coffee equivalent to over 5kg of beans (Cibelli et al.)

And while this probably was classic espresso or coffee, the market is vibrant with a still increasing market volume and parts of the market, such as fair-trade and especially instant-coffee products, that are growing much. 

One big part of processing coffee is roasting the beans, an energy intensive process that, after the agricultural impact and packaging, contributes most to the carbon footprint of coffee products. This is also what Gosalvitr et al. took a look at when calculating the life cycle costs of coffee in the UK.

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While there is a new study from Canada showing that the packaging, i.e. filter caffee versus capsule is very different, and surprisingly the capsule is supposedly better, the energy demand for instant coffee is higher than for just ground coffee (Viana et al.). As heat is the biggest part of that energy, we looked at how to decarbonize it. Spoiler alert: it really is a task easily solved in most cases. For industrial scale roasters, spray dryers and steam Kraftblock might be the best solution to use green energy for coffee production.

Process heat in coffee

With ground coffee, there is only one major heat-intensive process: roasting. Coffee is roasted either directly with a gas flame or indirectly by heating air. In any roaster, the simple principle is that hot air/gas flows around the beans, giving the green bean its typical roasted shape. 

There are several types of roasters, including drum roasters, hot air roasters, fluid bed roasters, and even centrifugal roasters. And while there are a lot of technical details behind the scenes, such as air circulation, heat recovery and cooling techniques, in most cases there is still a fossil fuel providing the heat, which in this application is between 150°C and 250°C to roast the coffee. This process takes anywhere from seven to 20 minutes, depending on the type of roast. 

And here is the first use case for Kraftblock. Instead of using fossil fuels, the process is electrified. This is especially easy in machines where clean hot air is already supplied and the machine is designed for it. Electrification with Kraftblock converts electricity into heat and then stores it. Since roasting can often be a batch process, storage has two advantages: One is that electricity can be purchased when it is cheap and then stored. The other is that the supply from the storage is flexible and can be adapted to the (changing) operating schedule. In the following animation video from a German manufacturer you can see how a drum roaster works.

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Decaf and Instant Coffee

Before roasting, beans can be decaffeinated. The most common method is to treat unroasted beans with steam and mild chemicals (Britannica). Steam can also be supplied via the Kraftblock and electrification, providing the same benefits of a carbon-free process. In this case, a steam generator is placed between the Kraftblock and the decaffeination process.

For instant coffee products, the coffee is ground after roasting and then spray dried. Spray drying is a technology that forms liquid droplets and then evaporates these droplets with hot air, in the coffee range of 160°C-185°C. This is another way to incorporate the Kraftblock system. Since the storage unit emits hot air, it is only necessary to regulate the temperature.

Regarding the energy used to process and produce coffee and coffee products, we can see that there are simple solutions to make coffee production sustainable. By using Kraftblock, it is also cheaper than fossil fuels for many states with a high share of renewable energy, and by using storage to shift the purchase of energy while keeping the supply the same, it is drastically cheaper than direct electrification.

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Sources:

Piya Gosalvitr, Rosa M. Cuéllar-Franca, Robin Smith, Adisa Azapagic (2023): An environmental and economic sustainability assessment of coffee production in the UK. Chemical Engineering Journal, Volume 465 https://doi.org/10.1016/j.cej.2023.142793. (https://www.sciencedirect.com/science/article/pii/S1385894723015243)

Luciano Rodrigues Viana, Charles Marty, Jean-François Boucher, Pierre-Luc Dessureault (2023): Here’s how your cup of coffee contributes to climate change. Online: https://theconversation.com/heres-how-your-cup-of-coffee-contributes-to-climate-change-196648 

Matteo Cibelli, Alessio Cimini, Mauro Moresi (2021): Carbon Footprint of Different Coffee Brewing Methods. CHEMICAL ENGINEERING TRANSACTIONS VOL. 76, 2020. Online: https://www.aidic.it/eff2021/programma/54cibelli.pdf 

Britannica: How Is Coffee Decaffeinated? Online: https://www.britannica.com/story/how-is-coffee-decaffeinated#:~:text=The%20most%2Dcommon%20methods%20of,to%20flush%20away%20the%20caffeine.

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