October 8


How To Remove Algae From a Coffee Reservoir (Easy Guide)

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Many people can’t even imagine starting their day without a cup of coffee. Still, most people don’t know how quickly appliances and various coffee makers can become a breeding ground for algae, bacteria, and mold. If your water reservoir looks like an unkempt pool, here’s an easy solution! 

The best way to remove algae from a coffee reservoir is by using a mixture of white vinegar and water in equal parts. Running the vinegar through a brewing cycle will disinfect and sanitize your coffee machine of any algae or mold. If you don’t have white vinegar, citric acid has the same effect.

In this article, I’ll take you through the cleaning process step by step. I’ll also present you with other cleaning techniques and explain how to prevent algae growth in your coffee machine water reservoir.

1. Unplug the Coffee Machine

This one should go without saying because electro-shock therapy is most definitely the wrong way to treat your gloomy, noncaffeinated disposition. Even if you haven’t had your first cup of coffee yet, you should be very careful when handling electronic appliances like your coffee machine. 

So, to be on the safe side, make sure that your coffee machine is unplugged before you set out to cleaning its water reservoir!

2. Washing It Only With Water Won’t Help in the Long Run

Bacteria and mold require a water temperature of 140°F (60°C) to be destroyed. However, since algae are quite resistant and thrive in a multitude of environments and temperatures, using vinegar is a safer solution for keeping your coffee machine water reservoir clean.

3. Clean Out Your Filter and the Water Reservoir

Before you can start the stage of inner cleaning, make sure to get rid of all the leftover coffee, throw out the filter, and get rid of the algae-infested water from your reservoir. This will ensure no debris keeps cycling through your coffee machine while you clean it.

4. Fill the Coffee Reservoir With the Water and Vinegar Mixture

Bring equal amounts of water and vinegar to a boil and fill the reservoir to the maximum. Then, leave the mixture to do its thing for half an hour. Vinegar has antibacterial and antifungal properties, and by making the water solution acidic, it also kills algae and prevents them from growing again. 

Save some of the preboiled unused mixtures for wiping down the outside of the coffee machine.

5. Turn the Coffee Machine on and Start a Brewing Cycle With the Water and Vinegar Mixture

Turning the coffee machine on and starting a brewing cycle will clean out the inner part of the coffee machine. At the same time, the boiling mixture will also perform another critical part of the coffee machine cleanup routine: descaling. 

Descaling is the process that removes all the limescale buildup in the coffee machine, making it run smoother and more efficiently.

6. Repeat the Process With 3% Hydrogen Peroxide

If you want to make sure you have gotten rid of all the algae in your coffee reservoir, pour a mixture of one part 3% hydrogen peroxide and two parts water into it. Start a brewing cycle with the mixture and leave it sitting for half an hour. 

Hydrogen peroxide also kills algae, mold, and bacteria, but it is also somewhat corrosive, so make sure you don’t leave it sitting for more than an hour. This is not an integral part of the process, but it will give you the peace of mind you probably need after discovering you have been making your cup of joe with the addition of green slime. 

7. Run As Many Brewing Cycles With Water As Required

Run water through the coffee machine as many times as you need to. Do this until you no longer feel the acidic smell from the vinegar. It might take a while, tho, so make sure to have your smartphone nearby–this might require more than a few levels of Candy Crush Saga. 

8. Wash All the Removable Parts

Give all the removable parts like the lid, brew basket, filter, and coffee pot a wash in warm, soapy water. Use a sponge and clean them thoroughly. This will get rid of all the grime, coffee, and fat deposits. 

You can also check if they have the ‘dishwasher safe’ symbol and let it do the work for you. No need to work hard if you can work smart.

9. Don’t Forget the Outside!

Beauty is in the eye of the beholder, and it’s what’s on the inside that counts, sure, but make your coffee machine look pretty. Pamper it by wiping it down–that one is a must. Use a soft cloth, vinegar, and water solution until it shines like the first day you bought it.

10. Do a Deep Clean Every Month

This type of deep cleaning should be done once every month to prevent algae growth. Also, make sure not to leave the ground coffee sitting in the machine for long periods of time because it tends to develop mold. 

Here is a simple Youtube tutorial to make the process easier:

Try doing a simple cleanup after every use – throw away the grounds and clean the basket and the filter. Once a week, wash all the detachable parts.

Things You Can Use if You Don’t Have White Vinegar

In case you don’t have white vinegar or just abhor the smell of it and, potentially, the taste, there are a few other options you can use for cleaning your coffee machine water reservoir. Citric acid, lemon juice, borax, or baking soda are fantastic substitutes for white vinegar.

Citric Acid and Lemon Juice

Unlike vinegar, lemon juice and citric acid have a pleasant smell.

Here’s how to use lemon juice to clean your reservoir: 

  1. Pour half a cup of lemon juice and fill the reservoir to the maximum, or dilute citric acid in water in a 1 to 250 ratio.
  2. Run it through the machine as you would the water and vinegar mixture.
  3. Run a cycle of water through the machine.


Here’s how to use borax to clean your coffee reservoir.:

  1. Mix 2 tablespoons of borax with a few cups of hot water.
  2. Run it through the brewing cycle.
  3. Run water through the machine at least 3 times to get rid of all the remaining borax in the system because even though it’s a great cleaning product, it’s an irritant when ingested.

Baking Soda

The active component in baking soda (bicarbonate) is a well-used algae killer–in addition to cleaning coffee machines, it is often used to clean pools and lakes of algae without affecting the microclimate.

Here’s how to clean your coffee machine using baking soda:

  1. Fill the coffee machine water reservoir with water and add a quarter of a cup of baking soda.
  2. Run it through the brewing cycle once.
  3. Rinse the system with water until it runs clean.

Do not, under any circumstance, use alcohol to clean your coffee machine. When alcohol is heated up (like during the brewing process), it produces vapors that can catch on fire. 

This can be caused by a spark caused by static electricity and can end in catastrophic result as an explosion or a house fire.

How To Recognize Algae in Your Coffee Machine Water Reservoir

If you notice a brown or green film or feel a slimy, slippery substance when you run your finger down the wall of your coffee reservoir–congratulations, it’s algae! Algae love moist places and need light to flourish, so your always-wet coffee machine near a kitchen window that gets a lot of sun is a veritable playground for these photosynthetic aquatic organisms. 

Most algae are non-toxic to humans and won’t affect your health in any way, but they do bring an ick factor to the table, or better to say to the cup. If you wanted to consume greenery, you would just eat a salad, right?

How To Prevent Algae Growth in the Coffee Reservoir

To prevent algae from making your coffee reservoir their home, always use distilled water when brewing coffee. Regular tap water has residue and minerals which algae use as a buffet. 

Avoid using water that has been sitting in the reservoir for more than 12 hours. Rinsing the reservoir and adding fresh water takes a minute and helps to prevent algae growth immensely. 

Also, avoid keeping your machine in a place that receives a lot of sunlight. The most important factor for algae prevention is cleanliness, so clean your coffee machine regularly.


Cleaning the coffee reservoir is a simple and easy process, but it is an integral step in keeping your coffee machine safe and your coffee oh-so-tasty. Simple household staples such as vinegar, citric acid, or hydrogen peroxide are enough to keep the coffee machine water reservoir up to par, without you even having to go shopping to ensure a thorough clean. 

Use the steps mentioned above, leaving the algae in the oceans, aquariums, and ponds, and keeping your bean water hot and roasty.


remove algae from coffee reservoir

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