Why coffee makers start to sputter
Tap water carries dissolved minerals, mostly calcium and magnesium. Every time the machine heats water, a little of those minerals is left behind as scale, a chalky white crust inside the heating element and the narrow tubes. Over time the tubes narrow, water moves more slowly, and the machine gurgles, sputters and takes longer to brew. Scale can also make the water run cooler and leave coffee tasting flat or bitter.
Vinegar is a mild acid, and acid dissolves scale. It is the same chemistry as clearing hard water stains from a tap or shower door.
First, check the manual
This method is for standard drip coffee makers. Some pod machines and espresso machines specify their own descaling solution and process, and some makers advise against vinegar because it can affect seals or parts, or leave a taste that is hard to rinse out. Many machines also have a dedicated descaling mode. If your manual names a product or a process, follow it. It is the safest way to keep the machine working and any warranty intact.
What you need
- White vinegar
- Water
- A paper filter (or the machine's reusable filter, empty)
- Warm, soapy water and a soft cloth for the removable parts
Step by step
- Empty it. Throw out old grounds and any coffee left in the pot, and rinse the pot.
- Fill with half and half. Fill the reservoir to its maximum with equal parts white vinegar and water.
- Add an empty filter. Put a clean paper filter in the basket. It catches any loosened scale.
- Start a brew cycle. Run it as if you were making a full pot.
- Set it and forget it. For heavy scale, pause the machine halfway through and leave it for 30 to 60 minutes so the vinegar can soak inside, then let it finish.
- Pour it away. Discard the vinegar solution and the filter.
- Run two fresh-water cycles. Fill the reservoir with plain water and run a full cycle, then do it again with fresh water. This rinses out the vinegar and the loosened scale.
- Wash the removable parts. Wash the pot, the filter basket and the lid in warm, soapy water, rinse and let them dry. Wipe the outside and the warming plate when the machine is cool.
If you can still smell vinegar after two rinse cycles, run a third.
Check your manual first, and use the maker's descaler if it names one. Never mix bleach with vinegar or ammonia: bleach and acids release chlorine gas, and bleach and ammonia release chloramine gas, so do not add any other cleaner to the reservoir. Unplug the machine and let it cool before wiping the warming plate. And keep vinegar off any natural stone countertop under the machine, because acid etches marble and granite. Wipe up drips straight away.
How often to descale
Many people descale every one to three months. Hard water areas and machines used many times a day need it more often. The machine usually tells you: brewing gets slower, louder or sputtery, or white flakes appear in the pot.
Common mistakes
- Skipping the rinse cycles. One rinse is rarely enough. Two leaves the next pot tasting of coffee, not vinegar.
- Using vinegar on a machine whose manual says not to. Check before you start.
- Using straight vinegar every time. Half and half is enough for routine descaling.
- Forgetting the removable parts. Old coffee oils in the basket and pot make coffee bitter too.
- Leaving the pot on the warming plate empty. Turn the machine off when you finish.
What professionals use, and why
In offices and cafés, machines are usually descaled with a commercial descaling solution, often based on citric acid or another food-safe acid. It works the same way as vinegar but is made for the job, leaves less smell, and is what many machine makers specify. Larger machines are often fitted with a water filter that removes some of the minerals before they reach the machine, so scale builds up more slowly. And they follow a schedule, rather than waiting for the machine to start sputtering.
The office breakroom machine
- Put descaling on the calendar, for example the first Monday of every month, so it does not depend on whoever notices.
- Run it at the end of the day, so the rinse cycles are done before anyone wants coffee.
- Leave a sign on the machine while it is descaling, so nobody pours a cup of hot vinegar.
- Check the manual or the supplier. Leased and plumbed-in machines often have their own maintenance plan.
- Empty and rinse the pot daily. Old coffee sitting on a warming plate is the fastest route to a burnt smell.
- Hot mugs on meeting room tables leave white rings on wood. They often fade with gentle warmth. See how to remove water rings from a wood table.
If it still sputters or runs slowly
Repeat the cycle. A machine that has not been descaled for a long time may need two rounds.
Try the maker's descaler. A product designed for your machine can work better on heavy scale.
Check for a blockage. Grounds in the basket outlet or a clogged shower head (the part that drips water over the grounds) can slow brewing. Clean them with a soft brush.
If water leaks, it will not heat, or it trips the breaker, stop using it. That is a repair or replacement, not a cleaning job.
Frequently asked questions
How do you descale a coffee maker with vinegar?
Fill the reservoir with equal parts white vinegar and water, put an empty filter in the basket, and run a full brew cycle. Discard the solution, then run two full cycles with fresh water to rinse it out. Check your manual first, because some machines specify their own descaler.
How often should you descale a coffee maker?
Many people descale every one to three months. Machines in hard water areas or busy offices need it more often. Slow, noisy or sputtering brewing and white flakes in the pot are signs it is due.
Can I use vinegar on a pod or espresso machine?
Check the manual first. Some pod and espresso machines specify their own descaling solution and process, and some makers advise against vinegar. Following the manual is the safest way to protect the machine and any warranty.
How do I get the vinegar taste out of my coffee maker?
Run at least two full cycles with fresh water after descaling. If you can still smell vinegar, run a third.
Why is my coffee maker sputtering?
Usually because mineral scale has built up inside the heating element and tubes, which slows the water and makes the machine gurgle. Descaling dissolves the scale. A blocked basket outlet or shower head can also slow brewing.
How do you clean an office coffee machine?
Empty and rinse the pot and basket daily, and descale on a set schedule, such as once a month, at the end of the day with a sign on the machine. Leased or plumbed-in machines may have their own maintenance plan, so check with the supplier.
If it is the office breakroom you are looking after, you can find out more on our office cleaning page, and get more practical tips like this through our free cleaning tips sign-up.