What is the most sustainable way of making coffee?

Question

Which method of brewing coffee is the most sustainable?

The criteria being: minimal waste, minimal energy (no matter where it's produced)

I guess for the optimal solution it would be necessary to...

1. use organic and fair trade coffee
2. not heat more water than necessary
3. use a French press or a similar system that produces zero waste (filters, capsules, etc.). A French pressed coffee also contains more coffeine, so that I can drink less of it.
4. reuse or recycle the coffee grounds, for example as garden fertilizer.
5. buy the coffee beans in bigger bags (to minimize waste) and grind them myself

Am I missing on something or is something from this list not really necessary?

Answer 1

I live off-grid, so I did a lot of study on this topic. All used coffee grounds make good fertilizer.

Drip machines seem to use a lot of energy, and they seem to use it for a lot of time. They also use disposable filters. Drip machines are kind of on the off-grid "blacklist".

Percolators waste a lot of energy because they have to keep the water boiling for a while, but they don't have any waste products. (I bet they also lose more steam.)

Espresso Machines may use more energy per volume because it heats the water hotter and uses a pump. The coffee also must be ground finer, but it's so much more concentrated that it might balance the energy consumption out. (I guess more extensive studies may be necessary.) They also don't have any waste products. Some people choose espresso because of the superior flavor.

French Press uses the least energy (depending on how the water is heated) as you only have to heat the water up once. The coffee is supposed to be a coarse ground, which can also save trace amounts of energy. It has no waste products. If you want to heat the water with electricity, electric teapots (with the heating element actually inside the water) seem to be very efficient and fast. With no waste products and maximum efficiency, French Press is often considered the best way to go.

If you really want to minimize your energy use and increase your sustainability, then you can grind it by hand, but other than that, it's hard to know if pre-ground or home ground is more efficient. If you buy in bulk, that definitely reduces shipping and packaging waste. Overall, your list looks pretty good.

---------Update--------

I've started making cold brew coffee, and I love it. I've got a 1-gallon water dispenser that has a large cylindrical strainer in it. You scoop your coffee grounds into the strainer, you fill the dispenser with cold water, and then leave it in the fridge for about 20 hours. It is the easiest coffee to make ever. You can store it in the refrigerator for a week, and it still tastes fresh. If you already have a fridge, this method uses virtually no energy to make the coffee. Of course, it still takes energy to roast, grind, and transport the beans. In my tests, my cold brew tastes better than my french press, but your mileage may vary. The one I'm using is called "Cold Brew On Tap," but there are many other comparable products.

Answer 2

Your grinder may be less efficient than a commercial unit, and shipping beans rather than ground coffee may affect the bulk for shipping. If you use extra (hot) water in washing a permanent filter you may be better off using unbleached paper filters and composting them along with the grounds. I find that you can't put lots of coffee grounds through a dishwasher without clogging the filter so pre-rinsing is necessary there. A drip machine used with paper filters doesn't need to be washed every time it's used.

This is one of the many cases where you're trading off water, energy and materials, so a direct comparison isn't possible.

Another option I've used recently, when bike-touring, is a coffee sock. This is simply a cotton bag (I made one from a spare cheesecloth) that fits in a mug, held over the rim by a drawstring or elastic. The coffee goes in, then the water. When done, tip out the coffee grounds and compost. Some rinsing is needed, though this might not be every use. With a suitable (e.g. enamel) mug you can add coffee and cold water, than heat. That's the attraction for me when camping.

Answer 3

Cold brew, which is essentially soaking the beans for 24 hours would only call for energy to roast the beans and to filter them. If you used a metal filter, there wouldn't be ongoing disposable costs, but some quantity of energy is needed to create the metal filter.

If you used the lightest roast, that would minimize the the energy used in roasting.

In any case, coffee from beans calls for transportation of the beans and fast transportation, since they only last about two weeks before the coffee taste like crap. So the economist in me says the most shelf stable and flat out cheapest source of caffeine might use the fewest inputs, and that would be caffeine pills or instant coffee.

Answer 4

TL;DR

• Get your coffee beans with rainforest alliance certification
• Drink it black or with non-dairy whiteners

Full answer:

I think the points you mention are relatively trivial compared to the big things:

• Where the coffee comes from and how it is transported
• If you add milk

Professor Mark Maslin and PhD student Carmen Nab have analysed the environmental impact, and they found:

Growing a single kilogram of Arabica coffee in [Brazil or Vietnam] and exporting it to the UK produces greenhouse gas emissions equivalent to 15.33 kg of carbon dioxide on average. That’s raw, pre-roasted beans (otherwise known as “green coffee”) produced using conventional methods. But by using less fertiliser, managing water and energy use more efficiently during milling and exporting the beans by cargo ship rather than aeroplane, that figure falls to 3.51 kg of CO₂ equivalent per kg of coffee.

The average cup of coffee contains about 18g of green coffee, so 1 kg of it can make 56 espressos. Just one espresso has an average carbon footprint of about 0.28 kg, but it could be as little as 0.06 kg if grown sustainably.

But what if you like your coffee with milk? Lattes have a carbon footprint of about 0.55 kg, followed by cappuccinos on 0.41 kg and flat whites on 0.34 kg. But when the coffee is produced sustainably, these values fall to 0.33 kg, 0.2 kg and 0.13 kg respectively. Using non-dairy milk alternatives is one way to make white coffee more green.

Answer 5

For your health you should consider the best ways to produce and recycle filter paper.

"The problem with French press and other types of unfiltered coffee techniques lies with blood lipids. Compounds from coffee can raise total cholesterol, triglycerides and bad LDL cholesterol (European Journal of Clinical Nutrition, August 2012). The culprits are in coffee oils that get trapped by filters, so people drinking filtered coffee should get the benefits without the higher cholesterol." -- from: People’s Pharmacy: Coffee has benefits, but not French press

Also see "Cafestol extraction yield from different coffee brew mechanisms"

Answer 6

Long term, forget drinking coffee.

The current temperature rises due to climate change is going to make less and less of the land that currently grows coffee viable for this purpose

Ethiopia - Speciality coffees will become impossible to make

Colombia - Production yields vary by 40% year on year making small scale production unviable

Brazil - Coffee yield is already down by 20% in SE Brazil

Consumer behaviour is not going to change this!

Answer 7

For me it's single-use plastic Nescafe Dolce Gusto coffee capsules.

Sounds strange? Let me explain.

A coffee maker is generally tuned to make a certain amount of coffee. Some machines have adjustable drip rate allowing the coffee to be in contact with the water for longer duration. Even then, it's usually only ideal and/or possible to make at least 2 cups of coffee at a time. For example I have an old grinding coffee machine that actually can't grind the correct amount of coffee for 1 cup, I can only grind 2, 4, 6, 8 or 10 cups. But I drink only 1 cup at a time. Also another coffee machine I have that makes coffee for a large metallic thermos flask, has dual-setting drip rate. With this other coffee machine it might be possible to make only 1 cup, but the drip rate for small amounts is probably optimized for 2 cups and not 1 cup. The thermos flask is initially cold and if I make 1-2 cups only, it absolutely has to be pre-warmed with hot water. It requires 1.4 liters of hot water at a temperature of 80 degrees C (heated from 10 degrees C) to make it pre-warmed, requiring 0.11 kilowatt-hours of heat energy. 1 kWh of heat where I live produces 0.2 kg of emissions, so this water pre-warming alone causes 22 grams of CO₂ emissions. I could theoretically make the coffee to a cup directly eliminating the needed pre-warming but the machine isn't really designed for that. I would have to devise some solution to activate the switch that detects the presence of the thermos flask that doesn't detect the presence of a cup. I also have to have some stand for the cup so the top of the cup is higher, where the coffee drips.

A Nescafe Dolce Gusto single-use plastic capsule has 5 grams of plastic and 7 grams of coffee. The 5 grams of plastic cause about 13 grams of CO₂ emissions.

Because I live alone and drink only one cup of coffee at a time, the single-use plastic capsules really are the most sustainable.

So my options are:

• Make coffee with single-use capsules by a machine that makes single cup at a time: 13 grams of CO₂ emissions from plastic. It tastes perfect as the machine is designed for producing a single cup at a time
• Make coffee with a grinding machine: minimum 2 cups at a time, so 7 g extra coffee consumed, and at rate of 15 g/g (one kg of coffee produces 15 kg of CO₂ emissions), it produces 105 grams of CO₂ emissions from the extra wasted coffee alone.
• Make 1 cup of coffee into a thermos flask: 22 grams of CO₂ emissions from pre-heating the flask and it will taste strange because the "make only a small amount" drip-lock is not optimized for 1 cups, it's optimized for a slightly large amount of cups
• Make 2 cups of coffee into a thermos flask: 22 grams of CO₂ emissions from pre-heating the flask and 105 grams of emissions from extra cup
• Make 1 cup of coffee into a cup directly using the thermos flask machine replacing the thermos flask with a cup: now there's no extra emissions from the coffee-making, but the cup will taste strange due to making 1 cup only as opposed to 2, and I have to somehow fabricate some mechanism to activate the switch that detects the presence of the thermos flask, and also I have to somehow fabricate some stand for the coffee cup so it is high enough that the dripping coffee won't miss its target

Theoretically somebody might argue that fabricating the mechanism to activate the switch and fabricating the stand for the single coffee cup would be most sustainable, but then I would have to suffer strange-tasting coffee made by a machine that is optimized for more than one cup.

Also, typically ground coffee is sold in 500 gram containers. Non-opened, it stays fresh for long but when opened, the clock starts ticking. One container makes about 70 cups. For me, that lasts about 35 weeks as I drink most of the coffee not at home but rather at workplace. Usually even after a week from opening a 500 gram coffee container, it would change its taste even if perfectly stored. So if I throw it away when it's not perfect anymore, out of the 500 grams 486 grams would be left as waste. I suspect a plastic container with lid in refrigerator would allow storing the coffee for longer, but probably not for 35 weeks. So there might be waste from spoiled coffee anyway.