Tea or coffee, what would be the most sustainable choice? And what to say about different variations, within these two categories; green vs. black tea, and coffee with or without caffeine? Our LCA-intern Conor Brennan dove enthusiastically in to these questions and did an extensive research on the impact of our hot beverages. Read all about the results in this article.
This is an example of the insights you can get from an LCA study.
Did you know ...?
Caffeine is widely recognised as the force that drove the industrial revolution in the 18th century. Thanks to caffeine, workers could toil day and night drinking beverages, such as tea and coffee, ensuring industry would never sleep. Today, many of us rely on tea or coffee to boost our own productivity, focus and energy levels. This is especially the case in major cities, such as Amsterdam, where caffeine has been an important commodity since the 17th century.
Tea or coffee?
"Tea?" Is one of the most commonly asked questions in any Irish household. I, myself, prefer to start my day with a cup of coffee, but the answer to this rhetorical question is almost always, “Go on!”
So, I never really have an idea of how much caffeine I am consuming with each morning brew and obligatory cup of tea with my mother. One day after I had reached a threshold of caffeine and the shakes had subsided, I wondered: “which choice is better for me and for the environment, tea or coffee?”
Which choice of caffeinated beverage is best for the planet?
To find out, we compare different types of caffeinated beverages using an LCA. Specifically, we calculate the impact of making one cup (235ml) of tea and coffee. An LCA is a comprehensive environmental impact study which includes many different impact categories. First For this case we determine the impact on global warming, expressed in kg CO2eq, and then observe water consumption (L) at different phases of the life cycle of the caffeinated drinks.
Furthermore, because some of us are strictly Team Tea and others Team Coffee , we explore the impact of the choice of tea; Jasmine Tea or Earl Grey, and the choice of coffee; Caffeinated or Decaffeinated?
In the end, we will assess the impact on global warming from making a cup of tea or coffee to compare their impacts. Finally, we want to see what choice of tea or coffee could improve this impact, depending on which team you're on.
How do we approach this assessment?
To compare the environmental impacts, we will use a life cycle impact assessment method recommended by the European Commission: RéCiPe. To use this method, we need to define some aspects of the LCA.
- What is the scope?: First, we define the scope of our assessment. The scope determines which stages of a product’s life cycle are included in our model calculations. For the most complete picture, we will use a cradle-to-grave scope. This scope includes production, use and end of life stages as a cup of coffee is a final product, so using a cradle-to-grave life cycle is appropriate.
- What is the functional unit?: The functional unit acts as a quantitative description of the function or service. It is the basis of determining the reference flows of the product and clearly defines what the LCA practitioner is going to assess: a specific product, a process, or a cup of coffee, for example. For this LCA, the functional unit is defined as one cup of caffeinated beverage that will be consumed after being prepared.
- What impact categories will we look at?: These are the aspects of the environment that are impacted by our products. The RéCiPe method has a total of 18 midpoint impact indicators that go from global warming to land use, ionising radiation and ozone depletion.
Depending on the needs of the client, the practitioner will focus on categories more important for the case of study. To keep our assessment concise and relevant, we’ll focus on the key impact of global warming, and water scarcity. We will also touch on fossil resource scarcity as part of the decaffeination process.
What contributes to the environmental impact?
Using datasets available from the Ecoinvent 3.10 database we created a model that covers: raw material acquisition and processing, manufacturing, distribution, use phase, and end of life phases of the life cycle of one cup of each caffeinated beverage. Figure 1 below shows the impact on global warming over the different life cycle stages for each different beverage in this case.
Figure 1. Impact of life cycle stages of beverages on global warming (kg CO2eq).
Figure 1 illustrates that decaffeinated coffee beverages are the biggest contributors to global warming out of the beverages in this case. The impact from raw materials for Team Coffee vs Team Tea is significantly larger for coffee beverages. Overall, compared to a cup of tea, caffeinated and decaffeinated coffee beverages produce roughly 5 times more kg’s of CO2 over the entire life cycle. Drinking a cup of coffee is roughly the same as streaming a video for 3 hours from your phone [1].
So, where is this extra impact coming from in a decaffeinated drink?
It may come as a surprise to readers that the decaffeination process adds an impactful stage to the life cycle of this beverage. This manufacturing stage for decaffeination requires more energy and more water to prepare the green beans.
Choosing a decaffeinated coffee over regular coffee will contribute close to 14% more kg´s of CO2 to the total impact. Decaffeination adds nearly 48% more kg’s CO2 to the regular coffee manufactoring process, see figure 2.
To note, the determined impact to global warming during decaffeination for this model best describes the safest and cleanest way for extracting caffeine from coffee beans. A process that is exclusive to a handful of organisations in a small number of locations, Descamex in Vera Cruz, Mexico was chosen for this study as an example.
Considering that water is the main extracting element during safe decaffeination it was necessary to see which beverage would also consume the most litres of water, see figure 3.
Also known as the Mountain Water Process, it doesn’t use any harmful solvent or extractive chemicals; it simply uses water, temperature and osmosis to remove the caffeine. As a result of using this safer method, more water must be used than the regular processing of coffee and tea, as can be seen in figure 3.
Coffee beverages consume roughly 22% more water than tea beverages. While choosing decaffeinated coffee over regular means adding 17% more water to produce one cup of decaffeinated coffee.
Coffee beverages use roughly 4 more litres than the water needed for a cup of tea. You can clean all your dishes after a meal or have enough water to keep your plants alive for at least 5 more weeks[1], [2].
Despite being safer for humans when consuming, the Mountain Water Process is still a resource intensive process as can be seen in, figure 4. This illustrates during each stage of decaffeination where the majority of the impacts are in the categories of global warming (kg CO2 eq), fossil fuel scarcity (kg oil eq) and water consumption (L). The soaking and extracting phase account for almost all of the impact in these categories.
Using the safer approach also means that it nearly doubles the impact from the transport of the materials. For a safer decaffeinated beverage, your beans must make an extra journey along the way. Harvested and processed green beans bound for safe decaffeination travel from Rua Mogiana, Brazil to Vera Cruz, Mexico and then to Rotterdam, Netherlands for roasting. From there they go to the retailer in Amsterdam and the product ends its journey at the consumer's home.
Figure 5 shows the kg’s CO2eq produced from the transport of each different raw material for each beverage. The added 0.00206kg CO2eq attributed to the transport of 15gs of coffee to use for one cup is equivalent to watching a 4 minute YouTube video or using Instagram for a couple of minutes.
So last night, the hour I spent doom scrolling Instagram in bed would have produced the same kg of CO2 equivalent to transporting enough beans for 30 cups of coffee.
Team Tea vs Team Coffee
The result: Decaffeinated coffee is the largest contributor to global warming of the beverages.
Team Tea is the outright winner here with the least environmental impact compared to Team Coffee. Team Coffee contributes the most to global warming and is the biggest consumer of water. From Team Coffee, decaffeinated drinks are the most impactful. The large impact of coffee beverages is owed to the raw material acquisition and manufacturing.
There is very little difference in environmental impact between the choice of tea as the processes don’t change much between black tea and green tea, the only difference is distance from the origin of tea leaf. Both have no downstream processing outside of the country and arrive directly to the Netherlands from China.
Coffee consumes roughly 22% more water than a cup of tea, and one cup of decaf uses about 17% more water than regular coffee. More water is needed to prepare the green beans and added energy to heat the water for caffeine extraction. Further cleaning and drying requires water and energy also. Transport nearly doubles that of coffee and is 10 times more impactful to global warming than tea. This is due to the extra downstream processing and added transportation to the decaffeination site in Mexico before coming to the Netherlands.
How can your choice make a better impact?
Although the decaffeinated cup of coffee would be the best option for reducing caffeine levels in our waters it has wider environmental implications on global warming and water scarcity. By exploring alternative caffeine free beverages to decaffeinated coffee, it is possible to reduce your impact.
If you are considering switching sides to Team tea but still need that caffeine hit in the morning black tea could be your new morning brew, see figure 6. Green tea would be the safest and best choice for everyone!
So to answer my previous question, “which choice is better for me and for the environment, tea or coffee?”. The answer is tea and from now on I will gladly sit and have as many cups of tea as I am offered at home!
References
[1] Kasia, “What is the digital carbon footprint?,” Plan Be Eco. Accessed: Sep. 18, 2024. [Online]. Available: https://planbe.eco/en/blog/what-is-the-digital-carbon-footprint/
[2] CBS, “How many litres of water do we use per day? - The Netherlands in numbers | CBS,” How many litres of water do we use per day? - The Netherlands in numbers | CBS. Accessed: Sep. 18, 2024. [Online]. Available: https://longreads.cbs.nl/the-netherlands-in-numbers-2023/how-many-litres-of-water-do-we-use-per-day
[3] A. O’Connor, A. Steckelberg, and G. Potts, “Coffee vs. tea smackdown,” Washington Post. Accessed: Sep. 18, 2024. [Online]. Available: https://www.washingtonpost.com/wellness/interactive/2022/coffee-vs-tea-nutrition-health/
