What is coffee grounds and what to do with leftover coffee grounds after morning coffee?
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What is coffee grounds?
First, it is important to understand what is meant by coffee grounds. The used coffee grounds are the residue that remains after the brewing process. When brewing coffee in the morning, mix hot water with ground coffee.
After you finish your cup, you can partially see the remains of the coffee grounds. This depends on the brewing method, as a paper filter, for example, prevents a large part of the coffee grounds in the cup.
Although coffee grounds contain several highly “desirable” chemical components, they are generally considered waste and are typically discarded or used as compost.
Chemistry and coffee grounds
Coffee grounds are high in sugars, which make up about half its weight. Another 20% is made up of proteins and another 20% are lignins.
It contains significant amounts of potassium, nitrogen, magnesium and phosphorus. The amount of caffeine remaining in used coffee grounds is about 48% of fresh coffee grounds. Used coffee grounds contain significantly less tannins than fresh coffee grounds.
Coffee grounds also consist of fiber (47%), fat (24%), polysaccharides (13%) and protein (11%).
Carbohydrates in coffee grounds
Coffee beans are a rich source of polysaccharides (about 50% of green bean dry weight) composed primarily of mannan, galactomannan, arabinogalactan type II, and cellulose.
Mannan, the main polysaccharide in the coffee extract, is responsible for its high viscosity, which in turn influences the technological processes involved in the production of instant coffee.
Proteins in coffee grounds
Coffee beans can contain a significant amount of protein. Total nitrogen compounds in coffee are relatively stable between species or even during roasting, ranging from 8.5% to 13.6%.
That in the Sustainable Management of Coffee Industry study by products and Value Addition: A Review on Espresso Residues reported crude protein is between 12.8 and 16.9%. The average protein content of SCG after brewing instant coffee is 13.6%.
Minerals in coffee grounds
- Some of the minerals it contains are ash (approx. 1.6%), which according to ICP-AES analysis is composed of several minerals. Potassium is the most abundant element, followed by phosphorus and magnesium.
- Potassium is also the predominant mineral in the coffee bean and accounts for 40% of the oxide ash.
- Most minerals are easily extracted with hot water when preparing instant coffee. Your total mineral content includes:
- Potassium
- Magnesium
- Calcium
- Sodium
- Iron
- Copper
- Manganese
Production of coffee grounds
According to the CSA, the “golden mean” for preparing coffee is 55 grams per liter. That’s just under 14g for a 250ml cup. While this may seem small to individuals, billions of cups of coffee are consumed every day.
Perfect Daily Grind, the researcher and ambassador for BeKoffee, a company that makes products from used coffee grounds, reports that per capita consumption in Portugal averages 4.73 kg per year. With a population of just over 10 million Portuguese, that’s more than 48,000 tons per year.
While some countries recycle their coffee waste, globally about 75% ends up in landfill. The remaining 25% is mostly used to manufacture agricultural products such as fertilizers.
According to the BBVA, about 16.3 million 60-kilogram bags of coffee were consumed worldwide between 2020 and 2021, an increase of more than two million from global consumption of the drink in previous seasons.
Other examples are Australia, where 65,000 tons of coffee grounds are produced annually. In Spain, more than 22 million people drink at least one cup of coffee a day.
Discover the uses of coffee grounds
Gardening
It may surprise you to know that most soils do not contain all the nutrients needed for optimal plant growth. For azaleas, radishes and hydrangeas, for example. Acid-loving plants like coffee grounds because of the acidity.
Flowers absorb nutrients from the soil. Over time, the soil will deplete. As a result, future flowers will not have access to the same nutrients.
Coffee grounds contain numerous minerals that are important for flower growth. Some important examples are:
- Chrome,
- Magnesium,
- Phosphorus,
- Calcium,
- Iron,
- potassium and
- Nitrogen.
In addition, you can use coffee grounds to absorb heavy metals that might otherwise contaminate the floor. If you want to use coffee grounds in your garden, simply sprinkle them on the ground near your plants. They even attract earthworms to your flower bed and improve their health.
Fortune telling with coffee grounds
In divination and “divination”, the patterns of coffee grounds are used for predictions.
Compost with coffee grounds
You can also use coffee grounds for composting. If you can’t use it right away, composting is a way to save it for later. You can even use your compost as mulch.
When you choose to make your own compost bin, it’s a natural process that turns organic matter into a rich, dark-colored material. This material is called compost.
When you use compost in your garden or yard, it can retain water and nutrients in the soil. This is another way to improve the overall health of your plants.
If you want to get the most benefit from your composting process, you should try adding other items to your compost preparation. Examples include shredded newspaper and tree branches, eggshells, leaves, grass clippings, herbs, stale bread and even fruit and vegetable waste.
You should try not to add fats, oils, dairy products, fish or meat to the compost heap. If they decompose, they could endanger the rest of your compost preparation.
Other uses
Used coffee grounds are also used in other areas of the household, e.g. B. as an air freshener or as a soap cleaner. They can also be used industrially in biogas production or for waste water treatment.
Bioethanol can also be made from the sugar content of used coffee grounds after they have been defatted as a pre-treatment and usually hydrolyzed with dilute acid.
If you want to have a complete picture, you can check our blog with some more ideas.
Coffee grounds and other waste
Most used coffee is thrown straight into the bin without being separated or treated. After disposal, it ends up in landfill. At this point, it takes at least three months for the coffee grounds to begin to decompose in the anaerobic environment of the landfill.
Coffee grounds contain oils and other compounds that can make the soil more acidic. In landfills, this creates acidic leachate (liquid) that can damage the surrounding soil.
In addition, the decomposition of coffee waste in landfills also produces greenhouse gases.
These gases have additional impacts on the environment and contribute to climate change. Melanie says: “When coffee grounds are disposed of in landfills, methane is produced, which is a greenhouse gas. Methane is known to be more harmful than carbon dioxide”.
Throw away alternatives to coffee grounds?
According to biobean, the UK’s largest coffee grounds recycler, used coffee grounds retain more than a third of their flavor and aroma volatiles after brewing (What Happens to Used Coffee Grounds – Perfect Daily Grind”).
It is also claimed that coffee grounds have a high calorie content. While it cannot be eaten, it is a potential source of energy.
According to Bio-Bean, coffee grounds burn “20% hotter and longer” than dry wood fuel. It also has a lower carbon footprint compared to traditional fossil fuels.
The coffee grounds problem
Several organizations have recognized the “invisible” value of used coffee grounds. As well as bio- bean, which collects and recycles coffee grounds across the UK, there are a number of other organizations around the world that reuse coffee grounds for other purposes.
UpCycled uses coffee grounds and other natural ingredients to create skin care products. Another company, Kaffee Form, uses them to make sustainable coffee cups and saucers.
Used coffee grounds have great potential, both in terms of organic composting and energy recovery and the production of new materials.
It is already being used to produce biodiesel and heating pellets. Soon it will no longer be just a waste product, but will be considered a raw material for industry.
There is economic potential for reusing used coffee grounds on a larger scale. However, the cost of organizing such an initiative would be difficult to assess and would require a large number of actors (including coffee shops) who are the main consumers of coffee.
In addition, industrial-scale composting and recycling initiatives are costly and require significant investment in infrastructure, even if no land is reused.
While some countries are beginning to collect coffee grounds for processing and reuse, most do not have the systems in place to do so. Therefore, in many countries, landfill, reuse and composting are the only possible outcomes.
Conclusion
Coffee grounds are a great resource for farming as they have excellent organic properties that help improve plant nutrition and appearance. At the same time, by extending its useful life, it helps to reduce the amount of organic waste in landfills and landfills.
