If your morning cup of coffee has started tasting a little off—bitter, flat, or just not right—it might not be the beans. The real culprit could be hiding inside your drip coffee maker where you can’t see it: mineral buildup. Hard water contains calcium and magnesium that, over time, leaves chalky white deposits known as limescale inside your machine’s water reservoir, heating element, and internal tubing. This buildup not only messes with the flavor of your coffee but can actually shorten the lifespan of your brewer. The good news is that descaling your drip coffee maker is a simple, do-it-yourself task that every homeowner can handle in under an hour.

Think of descaling as a deep clean for your coffee maker’s internals. Every time you brew a pot, water flows through those mineral-coated passages, picking up tiny particles of scale and depositing them into your coffee. That’s why you might notice a metallic or chalky taste even when you’re using fresh, high-quality grounds. Worse, the scale acts like an insulator, coating the heating element and making your machine work harder and longer to bring water up to the right temperature. That extra heat and stress can eventually cause the heating element to fail, turning your trusty coffee maker into a very expensive paperweight.

So how do you know when it’s time to descale? Pay attention to a few telltale signs. If your brew cycle takes noticeably longer than it used to, if you hear strange gurgling or hissing noises, or if your coffee tastes more bitter than usual despite using the same beans, scale is likely the problem. Most manufacturers recommend descaling every three to six months, but if you live in an area with hard water, you might need to do it more often. A simple test: fill your water reservoir and let it sit for 30 minutes, then pour the water into a clear glass. If you see white flakes or a cloudy film, it’s time to descale.

You don’t need any fancy chemicals to get the job done. White vinegar is the most common and cost-effective option. It’s a mild acid that breaks down mineral deposits without damaging your machine. Start by emptying the carafe and removing any used coffee grounds or filters. Then mix equal parts white vinegar and water—usually about half a cup of each, enough to fill the reservoir to the maximum line. Pour the mixture into the water tank, place the empty carafe back in place, and start a regular brew cycle. About halfway through, when about half the liquid has dripped into the carafe, turn the machine off. Let it sit for thirty minutes. This soaking step lets the vinegar work its magic on stubborn scale. After the pause, turn the machine back on to finish the brew cycle. Once it’s done, dump the vinegar solution down the sink.

Now comes the important part: rinsing. You don’t want any vinegar taste lingering in your next pot of coffee. Fill the reservoir with fresh, cold water and run a full brew cycle. Empty the carafe, then repeat with another full batch of clean water. Some machines require three or even four rinse cycles to completely flush out the vinegar smell and taste. If you still catch a hint of vinegar after two cycles, run one more. Your nose will thank you.

If you prefer not to use vinegar because of the odor, commercial descaling solutions are widely available at grocery stores and online. They’re often formulated specifically for coffee makers and can be even more effective. Just follow the instructions on the package—typically you mix the solution with water, run a brew cycle, and then rinse thoroughly the same way you would after vinegar.

While you have your machine pulled apart, take a moment to clean the other parts. Wash the carafe, the lid, and the filter basket with warm, soapy water. A soft brush or a clean toothbrush can help scrub any residue out of nooks and crannies. If your machine has a removable showerhead—the part that sprays water over the coffee grounds—take that off and soak it in warm soapy water for a few minutes. Built-up coffee oils can clog the tiny holes, reducing water flow and giving you a weak brew.

Prevention is always easier than cure. To slow down future scale buildup, consider using filtered or distilled water in your coffee maker. Many home improvement stores sell inexpensive countertop water pitchers with a carbon filter that removes some minerals. You can also install a small water softener on your kitchen faucet. And make it a habit to run a quick water-only cycle once a week to keep any fresh mineral deposits from hardening. But no matter how careful you are, descaling will still be necessary eventually—it’s just part of the natural wear and tear of making coffee with tap water.

A well-maintained drip coffee maker is a joy to use every morning. Your first sip will taste clean, bright, and exactly as the roaster intended. Plus, you’ll save money by not having to replace your machine every year or two. So grab that bottle of vinegar or a commercial descaler, give your trusty brewer the spa treatment it deserves, and get back to enjoying the perfect cup of coffee.