We can never stress just how important good coffee beans are to a great cup of joe, and we go to painstaking lengths to ensure you are receiving the best quality beans, freshly and precisely roasted within 24 hours of shipping. You may already know we’re huge proponents of grinding your own beans, but sometimes even good coffee beans can be one of the reasons why your coffee tastes bad.

Brewing coffee is as much of an art as it a science. Once you know the common mistakes made with coffee beans, water, and equipment, you can be sure you’re making great-tasting brews.

Hey, we all have off days. And sometimes those off days come in the form of coffee that tastes bad. And not bad like “you’re never getting those beans again” bad, but bad like “this is my favorite coffee, and something has gone horribly wrong” bad. That’s okay. It happens. And we can help you learn how to not make the same mistake again.

Brewing coffee is as much of an art as it a science. Once you know the common mistakes made with coffee beans, water, and equipment, you can correct them and get back to making great-tasting brews.

There are several reasons why your coffee isn’t brewing as well as you want it to. Read on to distinguish between these common problems and accurately diagnose the issue with your coffee brewing.

YOUR GRIND IS TOO BIG/SMALL

The grind of your beans can make a huge difference in the flavor of your coffee. Why? Well, coffee grounds need to be soluble enough to impart good flavor but insoluble enough to stay out of your filter system.

If your coffee tastes weak or sour, your drink may be under-extracted. The bad taste comes from the acids in the bean dissolving early in the brewing process. Large coffee grounds can cause this unappealing flavor since they have more surface area and don’t dissolve enough during your brew.

If your coffee tastes super bitter, your drink may be over-extracted. This happens most often with too fine of a grind. Depending on the type of coffee you’re brewing, you may need to adjust the size of your grounds. How you grind coffee beans for espresso is different from your regular drip coffee.

How to Fix It: First things first, you must know which grind goes with what brewing method. If you’re making coffee with a French press, you want your coffee beans to be extremely coarse. On the opposite end of the spectrum, Turkish coffee requires beans ground as fine as powdered sugar. Remember, grinding your own beans is the best way to ensure a great-tasting cup of joe. It might seem inconvenient, but once you have a grinder to go with your coffee gear, you’ll wonder why you didn’t get one sooner.

YOUR WATER TEMPERATURE IS WRONG

It might seem arbitrary to the untrained eye, but we’ll never get tired of championing the perfect temperature for brewing coffee. We recommend 205°F (96°C) for any cup of coffee. Why? You want your water hot but not boiling. Too hot and you could destroy volatile oils and the subtler flavors of your beans. Too cool and your coffee will come out under-extracted… which is weak and not a great way to start your day.

How to Fix It: This one is an easy fix. Invest in a thermometer. It can be a traditional thermometer or a fancy laser one. And if you ever find yourself without a thermometer again? Simply bring your water to a boil and remove from heat for around 30 seconds before brewing.

YOUR TAP WATER ISN’T GREAT

It might taste fine to you, but particles in your tap water can have a huge impact on the flavor of your coffee. Brewing coffee is like a chemistry problem. You can throw off your equation when you introduce unknown elements.

How to Fix It: This one is another easy fix. Filter the water you use to brew your coffee. Remember, many tap water filters need to run cold for proper use.

YOUR EQUIPMENT IS DIRTY AND/OR YOU WERE PREVIOUSLY BREWING A DIFFERENT TYPE OF COFFEE

If you were running a different type of coffee through your machine, that old coffee will affect the flavor of your new coffee. Even worse is if the old coffee was *gasp* of inferior quality. This is like mixing chocolate cake batter in a bowl that used to have crushed garlic in it but was never washed. You will taste that garlic in your chocolate cake. Every palette is different, but we can bet that most people wouldn’t enjoy that.

It might not feel like you need to clean it out every time—after all, you only made coffee. Just a quick rinse and it’ll be fine, right? Well, no. If you don’t know how to clean a coffee maker, now’s the time to learn. That’s because we tend to only think about the coffee pot and the filter area. Just when was the last time you cleaned the reservoir of your drip coffee maker? If you don’t remember, it might be time to do a proper wash of your coffee gear.

How to Fix It: Properly clean your coffee maker. Your taste buds and your immune system will thank you.

YOUR EQUIPMENT IS OLD

Sure, your coffee pot has been with you through thick and thin. It brought you a little cup of happiness on even the worst days. But no one and nothing is immune to the perils of age. This is especially true if the quality of your coffee takes a nosedive for no apparent reason. Your beans are good, your water is filtered and heated properly, and your equipment is recently cleaned. If that’s the coffee mystery you have on your hands, you may need a new machine.

How to Fix It: There’s not much you can do if your equipment is starting to break down. Start looking for a new coffee maker or grinder, stat.

YOU USED THE WRONG EQUIPMENT

Sometimes we can get away with fudging our coffee gear. Making espresso without an espresso machine can produce great results… just not with the consistency and accuracy of an actual machine.

We wholeheartedly encourage you to look for workarounds (especially if you’re on a budget) but you might be at the point in your coffee exploration where an expensive machine makes sense. Another thing to watch out for is what you’re actually drinking your coffee from. We highly doubt you’re going to reach for a plastic cup when you want to pour your coffee, but just in case: don’t. Glass and ceramic mugs are best when you’re at home, while stainless steel travel mugs are best when you’re on the go.

How to Fix It: Try using the proper equipment for the type of coffee you want to make.

So your beans, water, and equipment aren’t the problem. That’s okay. Brewing coffee can be tricky, so there could be other reasons why your coffee tastes bad.

YOUR TIMING IS OFF

If you drink herbal tea, you might not care if it steeps a little longer than you mean to. That’s not how things work with coffee. If your brew runs too short or too long, you may have over or under-extracted coffee on your hands. For example, you can brew percolated coffee between six and ten minutes. That’s a huge time variable. If you’re trying a new recipe, a little experimentation may be necessary to find the best way to brew.

How to Fix It: Slowly adjust your timing to find what tastes best to you.

YOU’RE BREWING TOO MUCH COFFEE

Just like buying coffee beans in bulk, brewing coffee in bulk isn’t a great idea either. It may seem like it’ll save you time later, but coffee is best when it’s fresh out of the pot.

How to Fix It: Brew less coffee more often, especially when you’re at home. If you brew for exactly what you (or your guests) are going to drink, you’ll always have a fresh cup of coffee on hand.

YOU MADE A MISTAKE

Hey, it happens to the best of us. If you know what went wrong, great. If you don’t, think back over your brewing process. Maybe you didn’t measure the water correctly. Maybe you missed a step somewhere. It’s fine if you don’t remember where it could have gone wrong.

How to Fix It: Remember to take notes the next time you try that same brew. Write down every step, how much water and grounds you used, and even the temperature of the water. If the coffee tastes bad on the second test, start making adjustments until you suss out the problem.

YOU DON’T EVEN LIKE THAT KIND OF COFFEE

Remember, coffee is a food, and food is all about your personal tastes. Don’t force yourself to drink coffee that tastes bad to you.

How to Fix It: Try different beans and discover what you enjoy.

If you’ve tried all the above, and there’s still some funky flavor happening, there could be other factors causing problems.

BITTER?

If you brew with water that’s too hot, your coffee can end up tasting bitter. Other factors like stale beans (don’t buy too much coffee at a time – you should only buy enough to last a few weeks), brewing for too long, or a too-fine grind can also create a bitter flavor. Some tips to fix this are adding milk/sugar to the coffee, or even adding a tiny amount of salt to bring out the coffee’s natural flavor.

SOUR?

In comparison to bitter coffee, a sour coffee flavor is on the opposite end of the spectrum. A sour flavor is often caused by the under-extraction of coffee. When you don’t brew coffee long enough or the grounds are too large, this can easily occur. A quick fix for this is brewing your coffee for a little longer or adjusting your grind size to be a little finer.

BURNT?

Unless you’ve purchased green beans and accidentally overcooked them, this can also occur if you brew your coffee with too-hot water for too long. After you brew, it’s ideal to keep your coffee as warm as possible. Keeping it piping hot is only going to kill the flavor.

METALLIC?

If it’s not caused by build-up in your machine, this phenomenon is often caused by a problem with water flavor/quality. For those who brew with regular tap water, this problem can be a common occurrence. There can be traces of chlorine and other contaminants in tap water that alter the flavor of the water, so brewing with filtered or bottled water is the best choice.

WATERY?

Watered-down coffee is no fun and can be caused by a variety of factors. These factors include not using enough coffee to brew, not brewing for long enough, not brewing hot enough, or using a too-small grind size. To tackle this, start by adjusting your coffee/water ratio. Then you can check your brewing time, grind size, and water temperature.

LIKE PLASTIC?

If your coffee has a plastic taste, and the problem isn’t your water or brewing method, it’s probably your machine. Machines can cause this plastic-flavor phenomenon when they’re new, or when they’ve been overused and not given a good clean now and then. The most successful solution is deep cleaning your machine. Begin by washing your water reservoir (since these are normally plastic) and running a brew cycle with hot water. You can even run a cleaning brew cycle with 50/50 white vinegar and water, 50/50 baking soda/water, or 50/50 lemon juice and water.

NOW YOU (PROBABLY) KNOW WHY YOUR COFFEE TASTES BAD

So, you might find it a little easier to get a great cup of coffee again in your kitchen. Of course, some coffee conundrums go beyond these common problems. If that’s the case, don’t worry. Think back on your brew process, inspect your beans, or maybe look at getting new equipment. Change one variable at a time until you get to the bottom of your coffee problem.

It takes work to become an expert home barista, but with a little practice and tenacity when things go wrong, you’ll get the hang of it soon.

Happy Caffeinating!