Paper Cup vs Mug – What’s better for the Environment?

The cafe industry has reached a crisis point. Coffee and pastries are so easy to serve in a low-waste way, but the default today is single-use items for everything. That’s creating mountains of unnecessary trash. How much exactly? Worldwide, about 700 billion single-use cups are used every year. Paper cups account for almost 40% of these at about 245 billion paper cups worldwide in 2020. With so many out there it begs the question: is a paper cup sustainable?

Today we’re taking a deep dive into paper cup sustainability, or lack thereof. To put things in perspective, we’ll compare it to the tried and true coffee mug! If you want the short version, it’s that mugs are better in every way. If you want the details on how and why, keep reading.

Number of Uses

The biggest issue with single-use items, is that we only use them once. In fact, sometimes it’s even less than that. Have you ever had food delivered to you at home with a bunch of flimsy plastic cutlery? If you don’t use them, then they’re zero-use items. Similarly, some cafes serve espresso-based drinks (americanos, lattes, etc.) in two nested paper cups. Sometimes a double cup is in lieu of a cardboard sleeve, but not always.

Keep in mind that this blog is a judgement-free zone. I created an app to help people find eco-friendly cafes, and I still got burned with a double-cup-and-sleeve drink. So no judgement if this has happened to you. For a cafe with the word “mug” literally in its name (see photo), this was a major disappointment!

But let’s round up and say that we get an average of one drink per paper cup. How does a ceramic mug compare? A mug can easily get used thousands of times. Even if it chips or breaks, you can often repair the mug, or use it for a different purpose. Here I’ll assume that a mug is used 3,000 times before it is thrown away. Does 3,000 sound high? In the context of a cafe, it’s a pretty conservative estimate. That’s a little less than three uses a day for three years.

Break Even Point

The break-even point is another way to think about the number of uses of a reusable item. Since reusable items are more durable, producing them often requires more materials, energy, and water. The sustainability break-even point of a reusable item is the number of uses required to be less damaging to the environment than that many single-use items.

For mugs, I’ve seen anywhere from 15 to 150 uses given as the break even point. This is heavily dependent on how energy- and water-efficient your washing process is. Let’s take 120 uses as the break even point for a mug. That’s just 4% of our 3,000 lifetime uses for a mug. That means that using a mug is 96% better for the environment than paper cups. That’s 25 times better! But that’s still a little simplistic, let’s get into the specifics.

Three Life-cycle Stages

There are three big life-cycle stages to consider when assessing the environmental impact of a drinking container.

1. Production
2. Use
3. Disposal

For our purposes, material sourcing and final delivery are included in the production stage. Similarly, transit associated with disposal is included in the disposal stage. For a cup, the use stage consists of washing it so it can be used again. Single-use cups do not get washed, so they have no environmental impact associated with their use stage.

The final piece of the puzzle is that we want to calculate the amount of environmental impact per *use*, not per item. So our equation is:

( Production + Use + Disposal ) / Total Number of Uses = Environmental Impact Per Use

This generic formula is applicable whenever you want to compare a single-use item to its reusable alternative.

Environmental Footprint Categories

We can classify environmental impact into two big categories.

1. Greenhouse gas (GHG) emissions
2. Waste materials

Both are critical. A big issue with a lot of environmental impact analysis is that it ignores waste materials. In a previous post we explained that this is largely because GHGs are easier to measure and easier to offset. But at EcoRate we’re devoted to weighing both issues as best we can. So let’s start with the carbon footprint of paper cups, then cover the waste materials.

Greenhouse Gas Emissions from Paper Cups and Mugs

Paper cups emit GHGs in their production and disposal phases. Sourcing and refining raw materials and transporting finished products takes a lot of energy. In the case of transport, that energy is mostly in the form of oil products powering trucks and barges. It all adds up to an immense amount of carbon (or worse) in the atmosphere. We can use CO₂ equivalent (CO₂e) to weight different gasses according to their global warming potential. That lets us measure the damage in like terms, as if CO₂ were the only GHG causing all the damage.

Throughout its three life-cycle stages, the average paper coffee cup generates about 110 g of CO₂e. That may not sound like much at first, but keep in mind that a 12 oz. cup only weighs 8 g. The weight is more like 16g once we add in a standard plastic lid and cardboard sleeve. That means that each gram of actual paper cup product translates to 7 g of CO₂e created somewhere along the way. That’s wild!

To do better than that, a mug just has to emit less than 330 kg CO₂e in its lifetime. (That’s 110 g X 3,000 uses.) It takes about 1.4 kg CO₂e to produce a mug, or about 0.5 g per use. For the use (washing) stage, I have seen estimates between 2.5 and 8.5 g CO₂e per wash. EcoRate estimates this to be about 4g CO₂e. The eventual disposal of a mug causes a negligible amount of emissions per use. Altogether, this means that a mug’s CO₂e footprint is less than 5g per use. So the carbon footprint of a mug is dramatically lower than that of a paper cup.

Material Waste from Paper Cups and Mugs

It may surprise you to know that “paper” coffee cups are not even made of paper! Well, not entirely anyway. They’re mostly paper with a plastic sleeve lining the inside. That’s what keeps the paper part from getting wet. What difference does a little plastic make? The fact that it’s a mixed material makes a paper cup’s end of life very problematic.

Why not just recycle them? The plastic lining inside a paper cup makes it extremely difficult to recycle. That’s why only 1 in 400 paper coffee cups gets recycled in the UK. In the US that number is likely even closer to zero. These cups end up in landfills or, even worse, litter our streets, parks, and oceans.

By contrast, a ceramic mug is made from mostly inert and non-toxic material. Because they’re more durable and more attractive, mugs are fun to reuse for some other purpose. Like potting plants, or making a mosaic out of broken mug pieces. If they do end up in a landfill, mug are mostly neutral to the environment.

The staying power of ceramics can’t be overstated. Think about the beautiful jars and bowls from ancient civilizations that archeologists find. They are sought out and put on display in museums. Do you think paper cups will be dug up thousands of years from now and showcased as stunning relics from the past? Probably not.

It’s harder to quantify the environmental of impact of end-of-life waste than of GHGs. But mugs still come out decisively ahead in this category.

Water Use

Water use is a special subcategory of material waste. It’s easy to get the impression that all the water used washing mugs is wasted. It’s a great idea to try to use less water while washing dishes. Whether that’s by hand or with a high-efficiency dishwater, the savings can really add up. Using less water usually also means using less energy to heat the water, so it’s really win-win. That being said, washing a mug requires dramatically less water than producing and shipping a paper cup. It’s easy to get that backwards. We use water to wash dishes all the time, but we never see all the water paper mills and factories use. So this resource consumption is a bit hidden.

Luckily, Upstream Solutions recently shared their climate action toolkit. The toolkit includes several clear charts that show how reusable containers are dramatically better for the environment. One of these charts illustrates how much water reusables save. Mugs use about seven times less water!

Why does any water get used at all in the making of a paper cup? Water is used in many steps, but one big component is the bleaching and washing of the paper material to get a uniformly white color.

Health Risks of Paper Cups

So paper cups aren’t sustainable, but can they really be a health risk? The main health issue is that a paper cups plastic lining leeches contaminants into your coffee. One study that found that paper cups release an average of 25,000 microplastic particles into your hot coffee. It also found that lead and other heavy metals leech into your drink from the lining. If that scholarly article is a little hard to read through, this article from studyfinds.org does a good job of breaking it down. If you want to find out more about the issue of toxics from plastics, you can read this free report just released by the National Academies of Sciences, Engineering, and Medicine.

My take on the health risks of single-use disposables is that it’s another reason to opt for reusables. When I say that reusables are better in every way, your health is one of the ways. This research into the toxicity of materials does add a bit more to that. It shows that our reusables should also be made of non-toxic materials. That’s part of why this post compares a paper cup to a ceramic mug, rather than to a durable plastic mug.

Make a More Sustainable Choice

So is a paper cup sustainable? No. Years from now the paper coffee cup will be seen as the poster child of our waste-laden times.

But there are other great sustainable cup options. Choosing to use a ceramic mug instead of a paper cup for your daily coffee is easy and has so many benefits. Let’s recap. Unlike paper cups, ceramic mugs…

• release way fewer GHGs in their lifetime
• can last for thousands of uses
• are fun to reuse/upcycle in their end of life
• are mostly inert and non-toxic if thrown away
• save an enormous amount of water
• do not release microplastics into your coffee
• are much classier and more attractive
• encourage us to slow down and appreciate our coffee

Reusables for the Aesthetic Win

I hadn’t gotten into those last two points yet, so let’s talk about them. Purely aesthetically speaking, don’t you think that a mug looks and feels dramatically better than a paper cup? If you need some inspiration follow the #muglife hashtag or muglife subreddit. You’ll see how much people love their beautiful and expressive mugs.

Using a mug also encourages us to slow down and enjoy our coffee at a relaxing cafe rather than taking it on the go. Coffee is a ritual for a lot of people, so give it a bit more space to be an uplifting moment in your day.

EcoRate: Sustainable Cafe App

How do you even find a cafe that uses mugs instead of paper cups? I made EcoRate to help you find cafes based on how eco-friendly they are. On the EcoRate sustainability map, look for cafes whose mug icons have their handle on the right side. That means the cafe uses mugs for dine-in drinks. And if you’re more of a BYO-Thermos kind of person, the cafes that allow that have a heart in their icon. You can rate cafes in the app too, which lets you keep track of personalized sustainability metrics. I hope you’ll join EcoRate’s community of caffeinated sustainability enthusiasts. The more of us there are, the sooner we’ll be able to cut down on all the waste in the cafe industry.