How to Descale a Coffee Maker: Clear Mineral Buildup for Hotter, Faster Coffee

Quick answer: to descale a drip coffee maker, fill the reservoir with a descaling solution mixed as its label directs, or with equal parts white vinegar and water if your manual allows vinegar. Start a brew cycle, stop it halfway and let the solution sit for 30 to 60 minutes, then finish the cycle. Run two or three full reservoirs of fresh water through to rinse. Most machines need this every one to three months, more often with hard water.

Signs your coffee maker needs descaling

Scale is mostly calcium and magnesium left behind as water heats. It builds up where you can’t see it, in the heating element and the narrow tubes that carry water to the brew basket. Common signs include:

• Brewing takes noticeably longer than it used to
• Coffee comes out less hot, or tastes flat or bitter
• The machine gurgles, sputters or leaves water in the reservoir
• White, chalky crust around the shower head or inside the reservoir
• A “clean” or descale light, if your machine has one

What you’ll need

• Your coffee maker’s manual, or the descaling instructions from the manufacturer’s website
• A descaling solution labeled for coffee makers, or distilled white vinegar if the manual permits it
• Fresh water, ideally filtered if your tap water is very hard
• A paper filter (helps catch loosened scale)
• Dish soap, a soft sponge and a bottle brush for the carafe

Ready-made descalers based on citric or lactic acid rinse out more easily than vinegar and don’t leave a smell. Our guide to the best descalers for coffee makers explains the differences and which machines call for which type.

Step by step

1. Check the manual. Some machines have a dedicated descale button or cycle, and some makers specify a particular solution or advise against vinegar. If yours has instructions, they override the general steps here.
2. Empty and rinse. Throw out old grounds and filters, empty the carafe and pour out any water left in the reservoir.
3. Mix the solution. For a commercial descaler, dilute it exactly as the label says. For vinegar, fill the reservoir with equal parts white vinegar and water. With very heavy scale, some people use a stronger vinegar mix, but start with 1:1.
4. Put in an empty filter. Place a paper filter in the basket, with no coffee, and set the empty carafe on the warming plate.
5. Brew halfway, then pause. Start a brew cycle and switch the machine off when roughly half the solution has passed through. Let it sit for 30 to 60 minutes so the acid can dissolve scale inside.
6. Finish the cycle. Turn the machine back on and let the rest of the solution brew into the carafe. Discard it, along with the filter.
7. Repeat if needed. If a lot of white flakes came out or the brew is still slow, run a second round of solution.
8. Rinse with fresh water. Fill the reservoir with plain water and run a full cycle. Repeat two or three times, or until you can no longer smell vinegar or taste the descaler.
9. Wash the removable parts. Clean the carafe, lid and brew basket in warm, soapy water, or in the dishwasher if the manual says they’re dishwasher-safe. Wipe the warming plate and the area around the shower head with a damp cloth.

How often to descale

A common guideline is every one to three months, but your water decides. With hard water or daily brewing, monthly is sensible. With soft or filtered water, every three months or so may be plenty. If your machine has a descale indicator, follow it. Using filtered water slows buildup but doesn’t stop it entirely, so keep descaling on a schedule.

Scale isn’t the only thing that builds up. Coffee oils leave a brown film in the carafe and basket that can taste stale. A weekly wash of those parts with soap and water keeps flavor clean between descaling sessions.

Special cases and cautions

Thermal carafes. A stainless thermal carafe holds heat well but traps coffee oils and is hard to see inside. Wash it with a bottle brush, and check the care instructions before soaking it or putting it in the dishwasher, since some aren’t meant for either. If you’re shopping for a machine, our guide to the best drip coffee makers with a thermal carafe notes which carafes are easiest to clean.

Single-serve and pod machines. These have their own descale procedures, often with a specific solution and cycle. See how to clean and descale a Keurig for one example, and always follow your machine’s manual.

Espresso machines. Many makers warn against vinegar because it can damage seals and internal parts. Use only the descaler the manual specifies.

Never mix cleaners. Don’t combine vinegar with a commercial descaler or with bleach. Use one product, rinse completely and only then try something else.

Don’t forget the grinder. If you grind beans at home, old oils there can affect taste too. Our post on how to clean a coffee grinder walks through it.

Descaling questions

Is vinegar or descaler better for a coffee maker?

Both dissolve scale. Commercial descalers usually work faster, rinse out more easily and leave no smell, and some manufacturers require them. Vinegar is cheap and fine for many drip machines if the manual allows it.

How many times should I run water after descaling?

Usually two or three full reservoirs of fresh water. Keep going until the brewed water smells and tastes neutral.

Can I use apple cider vinegar to descale?

Plain distilled white vinegar is the usual choice because it’s clear and has no added flavor. Apple cider vinegar can leave a smell and isn’t necessary.

What happens if I never descale my coffee maker?

Scale keeps building, so the machine brews slower and cooler, and the heater has to work harder. Eventually it can clog or stop working.

Can I descale with lemon juice or citric acid?

Citric acid is the main ingredient in many descalers, so a powder made for coffee machines is a good option. Plain lemon juice is less predictable and can leave pulp behind, so a labeled product is the safer choice.