Knowledge Base

How do you drink your coffee? The impact of cow's milk vs. soy milk vs. oat milk

We use a case from our client Barista Company to compare the impact of cow's milk, soy milk and oat milk. How big is the difference?

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Cappuccino, caffé lattes, or latte macchiato; many people love their coffee with milk. And more and more people are opting for coffee with plant-based milk, a more sustainable alternative to cow's milk. But how big is the impact-difference? We use a case from our client Barista Company to compare the impact of cow's milk, soy milk and oat milk.

Barista Company is a catering company that makes people happy with a cup of coffee at various events. For their cappuccinos and café lattes, they use a base of an espresso shot; they make this with 10 grams of coffee. Then, 150 ml of milk is added to a cappuccino and 200 ml to a café latte.

The impact of coffee

To determine the impact, we calculate with emission factors. These are values that indicate how much CO2 emissions are associated with a certain product or activity. Sometimes these emission factors can be found in a database, sometimes you have to calculate these factors yourself.

The emission factor for 1 kg of coffee is 8.1 kg CO2-equivalent (source: Ecoinvent v3.8). This means that 1 kg of "dry" coffee has an impact of 8.1 kg CO2-eq.
Therefore, 10 grams of coffee has an impact of 81 grams CO2-eq.

CO2-eq is the global standard measure to express greenhouse gas emissions, based on the Global Warming Potential of the gas. Carbon dioxide, nitrous oxide, methane, etc., are all expressed in this; so you can easily compare the climate impact and add up the impact of different greenhouse gases. Read more about this in our knowledge base article "What's it all about with CO2".

Note: all impact figures in this article are from our research, for questions you can contact our LCA expert Nata Dovgalenok.

The impact of milk: cow, soy, and oat

Where does the impact of milk come from? It arises during the production, processing, and transport of the respective type of milk. This includes, for example, the impact associated with various agricultural machines (feeding systems, milking machines, machines to cultivate the land, etc.) and machines to pasteurize, package, cool, etc., the milk.

The process to make cow's milk, oat milk, or soy milk differs greatly. And therefore, the difference in impact is also significant.

We compare the impact for you:

- 1 Liter of oat milk has a climate impact of 0.3 kg CO2-eq (Oatly)

- 1 Liter of soy milk has a climate impact of 0.7 kg CO2-eq (Ecoinvent v3.8)

- 1 Liter of cow's milk has a climate impact of 1.8 kg CO2-eq (Ecoinvent v3.8).

Oat milk has the lowest climate impact: the impact is no less than 6 times smaller than that of cow's milk.

So, what is the impact of your cappuccino?

Let's look at the total impact of the coffee and the different milk variants.

To recap:

Cappuccino = 10 grams of coffee + 150 ml of milk

Café Latte = 10 grams of coffee + 200 ml of milk

The 10 grams of coffee are made into an espresso shot with 30 ml of water.

It takes 0.085 kWh to boil 1 liter of water, for 30 ml this comes out to 0.00255 kWh.

With 1 kWh of "average" Dutch electricity, an emission of 0.328 kg CO2-eq is associated.

Thus, the energy consumed to make the espresso contributes 0.8 grams CO2-eq.

In the table above, you see the total impact of a cappuccino and a café latte, for each of the three milk variants.

The case: Barista Company

Barista Company is a catering company that you can hire for events. The coffee trucks, counters, and baristas of Barista Company can be found at (business) events, trade shows, conferences, festivals, and parties throughout Western Europe.

Barista Company asked us to calculate the CO2 footprint for the year 2022; this was 195 tons CO2-eq. The majority of this impact was in the so-called scope 3 emissions; greenhouse gases that are indirectly released for the production of the product, in this case, your cup of coffee.

47% of these Scope 3 emissions came from cow's milk. Barista Company consumed 30,774 liters of cow's milk in 2022, which resulted in an impact of 56 tons CO2-eq.

Representation of the scope 3 emissions 'Purchased goods and services' of Barista Company

To reduce its total impact, Barista will use oat milk more often. In consultation with the client, oat milk can become the standard for making cappuccinos and café lattes.

If Barista Company were to replace 50% of all cow's milk with oat milk, the organisation would reduce its CO2 footprint by 12%; from 195 tons CO2-eq to 171 tons CO2-eq.

Chris van Eldijk, Barista Company: "The events sector is a sector with a significant environmental impact. And Barista Company serves more than a million cups of coffee each year; just think how much coffee and ingredients are needed for that. And how much waste is generated. That's why we wanted to know what our impact is, so we can take our responsibility. Thanks to the calculations of Hedgehog Company, we know where our impact occurs, and we can start to reduce it."

Frequently asked questions

The carbon impact differs significantly between milk types, with oat milk being the most sustainable option. According to the article's data, one liter of oat milk produces 0.3 kg of CO2-eq, soy milk produces 0.7 kg of CO2-eq, and cow's milk produces 1.8 kg of CO2-eq, making the climate impact of cow's milk six times larger than that of oat milk.

A coffee business can significantly reduce its carbon footprint by first calculating its emissions to identify major impact areas and then making targeted changes. For example, since purchased ingredients like milk can be a primary source of emissions, replacing cow's milk with a lower-impact alternative like oat milk can lead to substantial reductions, potentially cutting a company's total footprint by 12% by switching just half of its supply.

For a catering business, a majority of carbon emissions often come from indirect sources known as Scope 3 emissions, specifically from 'Purchased goods and services'. The article shows that for a coffee catering company, the ingredients it buys are the main contributor, with cow's milk alone accounting for 47% of its Scope 3 emissions and representing a major part of its total footprint.

Oat milk has the lowest environmental impact for use in coffee, making it a more sustainable alternative to other options. The climate impact of oat milk is just 0.3 kg of CO2-equivalent per liter, which is significantly less than soy milk (0.7 kg CO2-eq) and six times smaller than the impact of cow's milk (1.8 kg CO2-eq).

The total carbon footprint of a cappuccino varies greatly depending on the milk used. Based on calculations in the article, a cappuccino made with cow's milk has the highest impact at 352 grams of CO2-equivalent, while one made with soy milk is 187 grams. A cappuccino with oat milk has the lowest impact at just 127 grams of CO2-equivalent.

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This article is written by:
Clara
Clara
Head of Communications
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