How to unclog a sink clogged with coffee grounds?

In this text, we will answer the question: “How to unclog a sink clogged with coffee grounds?”. In addition, we will discuss why coffee grounds clog the sink. Finally, we will discuss the composition of coffee grounds and some applications for it.

How to unclog a sink clogged with coffee grounds?

To unclog a sink clogged with coffee grounds, use a plunger or boiling water. If coffee grounds are the main cause of clogs in your sink, the problem can be easily solved. For that:

  • Step 1: Boil 2 liters of water
  • Step 2: With minimal water in the sink, pour a good amount of dish soap down the drain. Then pour all the boiling water at once
  • Step 3: Wait a few minutes and see if the water has returned to normal flow. If you still haven’t resolved it, you can repeat the process

 Another effective way to solve the problem is to use a plunger:

  •  Step 1: Position the plunger on top of the drain, covering it completely, and press it, until you feel that it is firm and well sealed
  • Step 2: Press the plunger handle up and down at least 10 times. The vacuum formed by the plunger is able to push the agent causing the clogging and free the passage to water
  • Step 3: After the procedure, remove the plunger and check if the water has returned. Otherwise, repeat the process

Why do coffee grounds clog the sink?

Coffee grounds clog the sink because when you throw the coffee grounds down the drain, part of it sticks to the fat present on the walls of the plumbing and, over time, forms a layer capable of preventing the passage of water. Thus, coffee grounds are a strong clogging agent.

Therefore, the ideal is always to throw the coffee grounds in the trash. Another common form of clogged coffee grounds is the belief that it can serve as a plumbing agent, when in fact it works the other way around.

What is the composition of the coffee grounds?

The composition of the coffee grounds can vary depending on the method used to make the coffee. In the preparation of the beverage, such as instant coffee in which the beans after roasting and grinding are subjected to extraction with water at 175 °C under pressurized conditions to remove soluble solids and volatile compounds. 

When we talk about Espresso coffee, water, at a pressure of approximately 9 bar and a temperature of around 92 °C, passes through the ground coffee bean for the production of the beverage.

In this way, Espresso coffee beans are richer in organic compounds than depleted industrial beans.

There are numerous applications for coffee grounds, such as the use of it without pretreatment in the cultivation of mushrooms and in the adsorption of dyes cationic for wastewater treatments and the industrial coffee grounds in the formulation of bakery products due to the significant presence of antioxidant dietary fiber in the respective matrix.

Furthermore, it has health benefits for humans, as an in vitro research indicates that the polyphenols present in the coffee grounds can be fermented by microbiota and may inhibit cancer cell survival of colon.

However, most of these residues, rich in organic compounds, remain unused, being discarded from inappropriate and harmful to the environment.

Coffee beans are a rich source of polysaccharides, around 30 to 43% (dry basis), depending on the degree of roasting, being the main polysaccharides, galactomannans, type II arabinogalactans and cellulose.

Galactomannans represent approximately 50% of the total polysaccharides in the espresso coffee grounds, while arabinogalactans and cellulose represent equally proportions.

What are some applications of coffee grounds?

Coffee grounds can be applied to food products and the formation of biodegradable films. Seeking to reduce the problems caused by the production and disposal of conventional materials and in view of the large amount of waste generated by coffee production annually.

Polysaccharide films exhibit good barrier properties to carbon dioxide and oxygen gas. In addition to efficient oil and lipid barriers, but little resistance to water migration, so like protein films. 

On the other hand, the same does not happen with films based on lipids, due to their hydrophobic properties, especially those with higher point melts such as beeswax and carnauba wax. 

For the food industry, films with properties of barrier are interesting, as they prolong the shelf life of products, delaying some reactions physiological, enzymatic or microbiological, in addition to preventing food contact with unwanted solvents. Thus, the use of coffee grounds for this application is very promising.


In this text, we answered the question: “How to unclog a sink clogged with coffee grounds?”. In addition, we discussed why coffee grounds clog the sink. Finally, we discussed the composition of coffee grounds and some applications for it.


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