How to Remove Hard Water Stains from Glass Coffee Pot: Descaling 101

remove hard water stains from glass coffee pot

Like any other machine, coffee makers need proper care to function correctly. Other than cleaning it with the standard soap-and-water technique, knowing how to remove hard water stains from a glass coffee pot is essential to keep it working to its full capacity.

The good news is, you don’t need anything overly fancy or expensive. As long as you have vinegar and/or lemon, hard water stains are a problem of the past!

What Are Hard Water Stains?

Before we learn how to remove hard water stains from a glass coffee pot, let’s go over exactly what hard water stains are. Hard water stains, also known as limescale, mineral deposits, water deposits, and mineral buildups, are stains that are left behind after water evaporates from the pot. They can also occur in your coffee maker’s water reservoir if you leave water in it for too long.

They’re caused by high amounts of dissolved calcium and magnesium, both of which are found in water. Other than coffee pots, you’ll also find hard water stains in your bathtub, sink, and other bathroom fixtures. While they’re not an immediate health risk, they’re still a bit of a nuisance. Plus, they’re unpleasant to look at!

Author Note: If left to build up, hard water stains can be troublesome to remove. You’ll likely need harsh bleach and other chemicals, as well as some serious elbow grease, to completely remove these stains.

While bleach and bathroom chemicals do work, they’re not exactly the safest thing to use in glass coffee pots. There are several other kitchen-friendly alternatives you can use, which I’ll be breaking down for you today.

What Do Hard Water Stains Look Like?

A glass cup of espresso with natural foam sitting on top of a mirror table in a posh interior

Similar to other kinds of stains, hard water stains come in a variety of colors. This is because they often comprise various minerals, such as magnesium, calcium, manganese, brass, iron, and copper.

Magnesium and calcium leave chalky white residues — the ones you’ll typically see in coffee pots. Manganese hard water stains look brownish or black, while iron leaves reddish deposits.

If left to fester, these water stains may alter the taste and smell of your coffee to something unpleasant. However, they won’t make you sick.

Regardless of stain type, the cleaning process remains the same. If the stains are particularly tough, we recommend using professional descalers instead of natural substances. This is the easiest way to remove hard water stains from a glass coffee pot.

What Happens if We Don’t Descale a Glass Coffee Pot?

The process of removing the chalky mineral buildup caused by hard water stains is called descaling. These stains aren’t only unpleasant to look at, but they can also have a negative impact on your coffee pot’s efficiency through the following:

  • Mineral scale buildup may clog water flow, which in turn may cause your machine to stop working.
  • Limescale that builds up around the valves and seals on your coffee machine may lead to water leaks.
  • If the minerals deposit heavily on the heat source, water won’t reach the optimal brewing temperature. As a result, the flavor of your coffee beans won’t be fully extracted.
  • Limescale reduces your water heater’s efficiency and life span by 25 to 40%, according to a study by the S. Department of Energy.

When Is It Time to Descale Your Coffee Machine?

Most coffee makers, including drip coffee makers with carafes, have a light indicator that turns on to let you know when it’s time to descale your machine. However, if you own an older machine or a coffee pot with fewer bells and whistles, chances are it lacks that feature.

The good news is, hard water stains are easily visible due to the chalky white residue they leave. So, if your coffee tastes a little off or is colder than it usually is, it’s time to descale your coffee pot.

Author Note: Depending on your machine, the hardness of your water, and how you make your coffee, you might need to descale your machine several times every few weeks. Regardless, it’s best to descale your coffee maker at least once or twice a month.

How to Clean Hard Water Stains in Glass Coffee Pots

There are three known ways to effectively remove hard water stains from a coffee maker. All of the tools and ingredients needed are commonly found in a typical household. First, let’s start with vinegar.

Cleaning With Vinegar

Espresso glass with water

Vinegar is a remarkable cleaning agent. It contains acetic acid, which allows hard water deposits to soften and break down. The only downside to this technique is that vinegar leaves a strong, pungent odor if not cleaned out properly. This is the most common way to remove hard water stains from a glass coffee pot.

What You’ll Need

  • Water
  • Distilled white vinegar

Step 1: Empty Your Coffee Pot

Rinse out any residual liquid inside your coffee pot. Don’t forget to clean the grounds out of the brewing chamber, too.

Step 2: Pour the Vinegar Solution Into the Water Chamber

Fill the carafe with equal parts of white vinegar and water. Pour this mixture into the water chamber all the way up to its full capacity.

Step 3: Run Half a Brew Cycle

Start your machine and let your coffee maker brew the vinegar solution for half a cycle. Once done, turn it off.

Author Note: If you descale your coffee machine regularly, allow the vinegar solution to rest in the pot for 30 minutes. If you haven’t cleaned your machine in a while, and you have a particularly bad buildup, let it sit for an hour.

Step 4: Finish the Brew Cycle

After the allotted time is up, turn your coffee maker on and complete the other half of the brewing cycle.

Step 5: Rinse

Pour the vinegar solution into your sink. Return the carafe back to your coffee maker, fill the chamber with just enough water, and let the machine run once again.

Repeat this cycle two to three times while allowing your machine to cool after each time. Doing so will get rid of any lingering vinegar taste or smell.

Cleaning With Lemon

Just like vinegar, lemons contain acetic acid which softens hard water deposits. But the good thing about them is how they deodorize old coffee smells.

This method is a bit more hands-on, but it works just as well as the vinegar solution. It’s another common way to remove hard water stains from a glass coffee pot.

What You’ll Need

  • 1/2 cup of lemon juice or 2 fresh lemons cut into wedges
  • 1/2 cup of water
  • 4-5 tablespoons of salt

Step 1: Clean Your Carafe

Pour the salt into your carafe. Using a slightly wet sponge, rub the inside of the pot while focusing the most on the hard water stains.

The granules of the salt will act like sandpaper without scratching the glass.

Tip: If you’re using fresh lemons, mix the salt with grated rind for a more sparkling pot.

Step 2: Pour the Ingredients Into the Coffee Maker’s Reservoir

After rinsing your carafe, add the mentioned ingredients into the coffee maker’s reservoir, with the exception of salt. Let the mixture sit for 15 minutes.

Step 3: Run a Full Brew Cycle

Run the machine through a full cycle to let the lemon mixture break down the mineral deposits.

Step 4: Rinse

Run a plain water cycle through the machine after it’s clean to ensure no lemon essence lingers and finds its way into your morning brew. Wipe down the exterior of your coffee maker, wash the carafe one final time, and you’re all done!

Cleaning With Commercial Descaler

Cracked cup with black coffee spilled on white table

Specifically formulated for descaling coffee makers, commercial descalers will keep your machine running reliably without worrying about any vinegar or lemon aftertaste. The process is almost similar to that of vinegar, except you don’t have to go through the rinsing process more than once.

My personal favorite descaler is the one made by Impresa. I’ve found that this product removes mineral buildup more efficiently than other commercially made descalers. On top of that, it’s also compatible with all types of coffee and espresso machines. This is the most effective way (albeit expensive) way to remove hard water stains from a glass coffee pot.

Useful Tips to Keep in Mind While Cleaning Glass Coffee Pots

To keep your glass coffee machine in tiptop shape, keep these tips in mind:

  • Use bottled or spring water instead of softened or distilled water as the latter two tend to have lesser concentrations of calcium and magnesium than the former.
  • Avoid using abrasive scouring pads or other rough fabrics to prevent scratches.
  • If you choose to wash your glass coffee pot in a dishwasher, don’t place it in the lower rack as it may melt the plastic handle of the pot.
  • Never rinse a hot glass coffee pot with cold water as the glass may crack or shatter.
  • Wash the removable parts, such as the filter basket and carafe, with dish soap after every use.
  • Leave the reservoir’s lid open after use so it can dry out completely to prevent germs or bacteria.
  • Descale your machine once or twice every month.

Final Thoughts

To keep enjoying the best coffee your machine is able to produce, it’s important to know how to remove hard water stains from glass coffee pots. If left to build up, these stains may hinder your machine’s efficiency, dull the taste of your coffee, and make your glass pot look unsightly.

Luckily, the hard stains found on coffee pots aren’t as difficult to remove as the hard water stains found in bathrooms. You don’t need bleach or highly concentrated chemicals to remove them; a simple vinegar or lemon solution will work wonders!

Stay caffeinated friends!

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