As a water treatment engineer, prevention and treatment of bacterial growth and scale formation (aka limescale) from calcium and magnesium (contributors to hard water) are common problems I have to tackle.
Luckily in a coffee maker these are generally easy to handle with acidic cleaning agents. The acid cleans the coffee maker and removes the scale through a reaction that forms carbon dioxide, water, and a soluble salt.
You should clean your coffee maker if the coffee has an odd smell or taste, if you can see a white scale forming, or if it takes longer than normal to brew.
Continue reading for all the details on how to get a clean coffee maker.
How Often to Clean
After each brew you should do a basic clean of your coffee maker’s parts with warm soapy water. If possible, empty any remaining water in the water tank to allow it to dry completely.
Doing this basic clean after each use will help prevent the buildup of scale and growth of mold and yeast. These can make your coffee taste worse.
You should do a deep clean of your machine about every three months to remove any scale and help sanitize the coffee maker. If you have hard water, you’ll want to do a deep clean on a monthly basis.
What You’ll Need
Here is a list of the basic tools and materials needed for doing basic and deep cleans of your coffee machine:
- Distilled white vinegar
- Water (distilled if possible)
- Dishwashing soap
- Sponge
- Paper towels or cloth towel
Instructions to Get a Clean Coffee Maker
Below are step-by-step instructions for cleaning your coffee maker. Some coffee makers have built-in cleaning cycles/functions and specific instructions on cleaning. Always review and follow those instructions before doing any cleaning.
Step 1 – Do a Basic Clean
Remove any used coffee grounds from the filter basket. Clean the filter basket, carafe, and water tank (if removable) with warm soapy water using your sponge.
Use a paper towel or cloth towel to clean the carafe warmer and the water distributor on the machine above the filter basket. If excess water sits on the distributor and evaporates, it will start the formation of scale.
If you plan to do a deep clean, continue to Step 2. If you’re only doing a basic clean, then stop here leave all the parts out and open to dry completely.
Step 2 – Create the cleaning solution using vinegar
Fill the water tank to its max fill line using equal parts of the distilled white vinegar and warm water. See the end of this article for a list of alternatives to white vinegar.
Step 3 – Run a Brew or Clean Cycle
Place the carafe and filter basket back in the machine. If your coffee maker doesn’t have a reusable filter included with the basket, add a paper filter in the basket.
Your machine may or may not have a built-in cleaning cycle. If it does, start the cleaning cycle to run the vinegar solution through the machine.
If the machine doesn’t have a built-in cleaning cycle, start a normal brew. When it’s halfway complete, turn the machine off and let it sit for 15-30 minutes. The longer you let it sit, the more time the vinegar will be in contact with the scale inside the machine. After it sits, turn the machine on and start another brew to finish the cycle.
Step 4 – Repeat Brew or Clean Cycle
If you have heavy scale build-up in your machine, you can opt to repeat Step 3 using the same vinegar solution or a fresh batch. A fresh cleaning solution will clean better.
Step 5 – Flush with Clean Water
Once you have completed the brewing or cleaning cycle with the vinegar solution, dump the contents of the carafe down the drain. Rinse the water tank and then fill it with clean water (distilled if possible).
Run a brew cycle with the clean water to flush the vinegar from the system. Once the brew cycle is complete, empty the contents of the carafe and repeat a brew cycle with another batch of clean water.
Once the second cycle is complete, all of the vinegar should be removed. If you still smell it in the carafe, you can repeat flush cycles as many times as needed. You can test for vinegar in the water in the carafe by adding a teaspoon of baking soda to it. If the water fizzles when you add the baking soda, then vinegar is still present and you can run another flush cycle.
Step 7 – Clean the Exterior Parts
Once the internals of the coffee maker are clean, do a final clean of the machine’s exterior. Rinse the carafe, filter basket, and water tank (if removable) with clean water. Wipe the water distributor with a paper towel or cloth towel to remove any remaining water. Leave these parts out and open to completely dry.
Alternative Cleaning Solutions
If you don’t have distilled white vinegar available or want to try something different, use one of the alternative chemicals from the list below. Adjust the amount of each chemical as needed for your situation.
- Apple cider vinegar – This is very similar to white distilled vinegar, but it does have a different smell and is slightly less acidic, meaning it may not remove as much scale. Use equal parts apple cider vinegar and water.
- Lemon juice – Lemon juice (citric acid) is less acidic than vinegar so it’ll likely remove less scale, but it can be used in a pinch. The benefit of lemon juice is that it’ll give your coffee maker a nice lemony scent! Use equal parts lemon juice and water.
- Hydrogen peroxide – Hydrogen peroxide is readily available at grocery stores and pharmacies at a concentration of 3-5%. Use one part hydrogen peroxide to two parts water. Be careful when handling the hydrogen peroxide and following any instructions on the bottle.
- Alka seltzer tablets – These tablets contain citric acid and baking soda (see note below about baking soda). This is more of a last resort type option and may have varying levels of effectiveness depending on the amount of scale that’s built up. Fill the water tank and add 3-4 Alka Seltzer tablets to the tank (don’t overfill due to the bubbles that will form). Allow it to sit for about 15 minutes before starting a brew/cleaning cycle.
- CLR (Calcium, Lime, Rust) – This is more of a heavy duty cleaning agent for serious scale build-up. If you have hard water in your home, there’s a good chance you have this on-hand already. You need to check your coffee maker’s manual to make sure this cleaner is compatible. CLR shouldn’t be used on certain brands like Keurig, Cuisinart, and Gevalia. See CLR’s site for directions and other important notes.
- Commercial Cleaning Tablets – There are many cleaning tablets available (brands like Urnex, Jura, Cino, etc.). Follow the instructions that come with the product.
Baking soda was not included because it creates an alkaline solution (opposite of an acid) which isn’t successful at removing scale.
Tips
Below are some additional tips for cleaning and scale prevention.
- Consider using distilled water (“soft” water) for brewing if your home has very hard water.
- If you’re going to be away for a while, empty the water from the coffee maker and keep it open to dry out.
- If coffee is burnt on the inside of the carafe, you can clean it with rice. Add equal parts of warm water and distilled white vinegar to a level to cover the burn stain. Then add a few drops of dishwashing liquid and one cup of uncooked rice. Swirl the mixture in the carafe to allow the rice to scrub away the stain.
What to Do Next?
Once you get your coffee maker sparkling by doing a deep clean, be sure to maintain a regular cleaning schedule to keep your machine in tip-top shape and your coffee tasting its best.
And once it’s clean, check out our guide on the different types of coffee to check out a new drink to try with your machine!
