Hard Water

As it turns out, coffee is only as good as the water it is made with. If your coffee tastes metallic or off in any way, you may be brewing your morning roast with hard water, which is water that contains high levels of minerals. The calcium and magnesium in your tap water can absolutely change the taste of your brewed coffee or espresso shots.

A surefire way to find out if you are making your coffee with hard water is to fill up a cup, add a few squeezes of Castile soap, and wait. If the water turns milky or cloudy, you are dealing with hard water.

Over-Extraction

Do you like grinding your own beans at home instead of purchasing pre-ground roasts? Well, there’s a chance you are selecting the wrong grind size. Coffee extraction happens when you pour hot water over your grounds, which in turn pulls out the lipids, oils, and acids, along with the sugars and plant fibers out of the ground-up coffee.

If you set your grinder to a setting that is too fine, over-extraction can occur and cause a worrying metallic flavor. Additionally, if you do not regularly clean your coffee grinder, you might find that your mysterious metallic taste stems from it being unclean.

Dirty Coffee Machine

This one is obvious. A dirty machine can completely be responsible for that surprising metal taste in your mouth. If you aren’t cleaning your machine thoroughly and regularly, you will have more problems than just a metallic taste in coffee.

Minerals from water and bacteria can collect and germinate. Mold can even form inside your machine or water reservoir if your coffee machine is exceptionally grimy. At this level of filth, you should be concerned for your health and stop drinking coffee until you clean your coffee maker.

Your Coffee Machine is Leaching Metal

Leaching is a scientific term used to describe the process that takes place when a liquid is used to extract dissolvable particles from something solid. In your case, the liquid is the water you use to make your coffee, and the solid is any metal the water comes into contact with inside your coffee machine, French press, or Moka pot.

If this is the cause of your metallic taste in coffee, it shouldn’t come as that much of a surprise, as you are literally drinking coffee infused with metal ions.

Your Diet

Believe it or not, that metallic taste you are experiencing might not have anything to do with the quality of your water and beans—the taste may not even have anything to do with how well you do or do not clean your machine. It may, however, have everything to do with your diet or your prescribed medication.

Even taking iron supplements or eating snacks high in iron while sipping your brew may be enough to cause a metallic taste in coffee.

Solutions

Here are the remedies:

Change Your Coffee Beans

If your coffee beans are indeed the culprit for the metallic taste in your coffee, then consider trying out an alternate brand or a lighter roast. Make a point to buy whole beans and nothing pre-ground, for whole beans will maintain their flavor profile for longer. Moreover, you must not give in to the temptation of buying your coffee in bulk to make fewer trips to the market. Only buy what you need when needed to ensure a fresher and better-tasting cup of coffee.

Soften Your Water

Hard water is an easy problem to tackle and can be done by simply using bottled water instead of the tap. Alternatively, you can purchase a filter if you do not want to waste all that plastic. Reverse osmosis filters are the best for removing unwanted minerals and contaminants from your water.

Change Your Grind Setting

Experiment with the settings on your grinder. Place it on medium-fine and slowly move it to a courser setting. If your coffee tastes bitter and slightly metallic, your beans are ground too fine and are being over-extracted.

Oppositely, if your beans produce a sour, weak-tasting cup of coffee, chances are you are under-extracting your beans. Fine-tuning your grinder may take a few adjustments before you find the setting that is just right.

How and When to Clean Your Machine

You want to start by soaking your machine’s filter in warm, soapy water. Dish soap will work just fine. Next, pour equal parts water and vinegar into your coffee maker and brew this mixture as you would a regular pot of coffee. After this step, brew a few pots of only water to avoid your next cup tasting like vinegar.

Wiping down your machine’s exterior is also essential to keeping your coffee machine functioning at its full potential. Whether you use your coffee machine daily or a few times a week, you should clean it inside and out at least once every month.

How to Avoid Metal Leaching Into Your Cup

Avoid products made from aluminum or other metals. Stainless steel, while far superior to aluminum in the leaching department, can still transfer metal ions into your hot beverages. Instead, look for glass products such as the glass French press.

Stainless steel-lined pots are another way to avoid metal leaching and contaminating your coffee. Lastly, under no circumstance should you employ an abrasive brush to clean any metal piece of your coffee machine. Doing this will only exacerbate the problem.

Examine What You Are Eating and What Medication You Are Taking

Did you start noticing the metallic taste in your coffee when you started eating a particular food? Or did you start taking an iron supplement because you recently discovered you are anemic?

Take a good look at what you put into your body, and you may find what is responsible for coming between your tastebuds and your morning joe.

Final Thoughts

When you notice a metallic taste in coffee, start by focusing on the easy fixes, such as changing your beans or testing your water to see if it is hard. Play around with the settings on your grinder and see if you can make any headway there. If all of this fails, it is time to break your machine down and clean it.

Examine your coffee maker and French press closely. Do any of the metal components appear to be disintegrating? If your equipment looks good, think about what you ate right before you noticed your coffee tasting like metal. If your diet and supplement regimen have not changed, it may be time to buy yourself a brand-new coffee machine—because after all, you deserve the best.