Why Your Coffee Tastes Bad — And What to Do About It

If you’re a coffee lover, then you know how frustrating it can be when you’ve just finished brewing your coffee and you take the first sip, only to discover that it’s shockingly awful. So, why does your coffee taste so bad sometimes? And what can you do to fix it?

A bad taste in your coffee may be due to poor extraction or water that’s the wrong temperature. Using dirty brewing equipment or stale beans could also be the cause. To ensure you get the best taste, always give the coffee enough time to extract, use clean equipment, and brew with fresh beans.

Coffee brewing is as much a science as it is an art. Once you know the common causes of bad taste, rectifying the issue becomes much easier. Let’s jump into the details so that you can get back to enjoying a delightful cup every time.

What Makes Coffee Taste Bad? 

Woman suffering drink bad taste

There are several reasons why your coffee might taste particularly terrible. Here’s a quick overview of some of them:

Poor Extraction

It doesn’t matter what kind of equipment you’re using, be it a top-of-the-line espresso machine or a high-end drip coffee maker, poor extraction results in bad-tasting coffee. 

Since extraction bonds your hot water and your coffee grounds to form the brew, you’ll need enough heat, the correct coffee-to-water ratio, and the right grind size to ensure your coffee is extracted correctly. Any mistakes and you’ll end up with over-extracted or under-extracted coffee, which often tends to taste weird.

The key to avoiding poor extraction is having the right equipment. Find a grinder that suits your brewing style. Our favorite is the Cuisinart DCG-20BKN (on Amazon).

You’ll also want to use measuring devices to ensure the proper water temperature and coffee-to-water ratio. All in all, you need to keep practicing more for these things to be embedded in your brain. 

Using Stale Beans

Coffee beans don’t have an indefinite shelf life and start losing their flavor only a few days after roasting. Soon after the coffee beans are roasted, they begin to oxidize and the chemical composition of the flavor compounds within the coffee changes. Eventually, the coffee beans become stale.

As painful as it may be to throw away your beans, it’s what you need to do when they become stale. Try not to hold on to coffee beans for too long in the future, and always store your beans properly, away from heat and moisture, in an air-tight jar like this one (on Amazon)

Coffee tastes better when fresh (between four days and two weeks old), so be sure to make regular shopping trips and only buy what you need for the next week or two. While at it, check for the coffee label’s roast date rather than the expiration date.

The Roast Isn’t Correct

If you roast your beans, this could be the source of your coffee’s bad taste. Roasting is a tricky process that requires excellent attention to detail. 

While you can certainly roast your beans at home, you need to do it properly for the best results. Sometimes, things get out of hand, and the quality of your roast may plummet. We all have our bad days, so don’t freak out if yours turns out awful from time to time.

You couldn’t be more wrong if you think you’re safe because you buy store-brand coffee beans. As it turns out, industrial coffee roasters have trouble roasting beans consistently, meaning you could end up with a poorly roasted batch.

Consider trying a new recipe or finding good equipment substitutes for that ideal roast. If your store-brand roasted beans are bad, get a new batch of the same bean or switch the coffee type entirely.

Using the Wrong Water Temperature

The temperature of your water significantly impacts the taste of your coffee. The ideal temperature for making coffee is 195 to 205 degrees Fahrenheit. 

If your water goes beyond this point, you’ll boil off some of the oils that give your coffee its flavors. A water temperature below the threshold and your coffee won’t be adequately extracted, producing a weak coffee with little flavor.

To avoid this, buy a good thermometer (on Amazon) and monitor the temperature of your coffee water to ensure it’s right — or better yet, invest in a coffee maker with water temperature control.

Using the Wrong Equipment

The art of coffee brewing encourages creativity and improvisation. Still, if you go overboard and start using the wrong equipment for the type of coffee you’re making, you’re at risk of winding up with bad-tasting coffee.

While you might get away with using generic coffee-making equipment in some cases, you won’t be able to do so in others, like when making specialty coffees such as espresso and Turkish coffee, which call for specialized gear. Your best bet is to use the right equipment for the job.

Another thing you need to be mindful of is the cup you use to drink your coffee. Don’t reach for a plastic cup. Instead, use a ceramic or glass mug at home and stainless steel travel mugs when you’re on the go.

Using Dirty Equipment

Brewing coffee using a dirty espresso, French press, or coffee maker can undoubtedly mess up the taste of your drink. Imagine using a knife to chop some onions and then slicing an apple with that same knife.

You’ll be getting a slight taste of onion with your fruity snack. It’s similar to brewing coffee, so always clean your equipment thoroughly after use.

Sour vs. Bitter 

As we’ve already established, poor extraction leads to a funky-tasting cup of coffee.

Now, if you brew with water that’s too hot, your coffee will be over-extracted, resulting in a bitter flavor. Other issues like stale beans, brewing for too long, or using a grind that’s too fine can also create a bitter taste.

A quick fix for a bitter cup is adding milk, sugar, or even a little salt to bring out the coffee’s natural flavor.

On the other hand, a sour taste in your coffee can be due to under-extraction. Moreover, if you don’t brew your coffee long enough or use massive grounds, you’re bound to drink a sour cup. Solutions include brewing your coffee for a little longer or adjusting your grind size to be a bit finer.

Determining the Correct Grind Size 

The grind size of your beans can be a game changer in terms of how your coffee tastes. Coffee grounds need to be soluble enough to give off good flavor but also insoluble enough to keep out of your filter system.

If you use too-large coffee grounds for the type you’re brewing, you’ll have weak coffee that’s under-extracted and sour tasting. This mostly happens because huge coffee grounds have more volume in proportion to the surface area exposed to water.

When you brew your coffee, it becomes harder for the water to pull flavors out of the grounds. 

Conversely, when your coffee is ground too small for the brewing technique and equipment, all the flavors come out quickly and easily, leading to excess bitterness and other unpleasant flavors.

You need to know which grind size works best with the type of coffee you’re making and the equipment you’re using, then adjust the size of your grounds accordingly. For instance, if you’re making coffee with a French press (on Amazon), you want your beans to be coarse.

Grinding your beans is the best way to ensure you end up with appropriately-sized grounds. It might seem tedious, especially if you don’t have a burr grinder (on Amazon), but buying one will be the best decision you’ll ever make. You’ll wonder why you never got it sooner.

How Long Should Coffee Brew?

The longer you brew your coffee, the more flavor is extracted from the beans. However, if you brew too long, you’ll pull out too much flavor and end up with extremely bitter coffee. Inversely, if you brew for a very short time, you won’t extract enough compounds, and your coffee will be relatively tasteless.

How long you brew for will vary depending on the type of coffee and brewing method. The contact time should be about 2-4 minutes if you’re using a French press.

In a drip system, the time should be around 5 minutes. Espresso, though, has a relatively shorter brew time — only 20-30 seconds. A little experimentation is all you need to find what works for you.

Finding the Right Coffee-to-Water Ratio

Happy cropped young woman making coffee in kitchen

Finding an ideal coffee-to-water ratio can be much easier if you measure precisely using a kitchen scale (on Amazon). These ratios usually correspond with the weight in grams and often come down to your preferred style of coffee. To summarize how it works:

  • If you’re brewing regular coffee, use a 1:15 ratio. This implies that 1 part coffee grounds for 15 parts water. So, you’ll be fine with 30 grams of coarse coffee grounds for 450 grams (16 oz) of water.
  • For immersion coffee like the French press, aim for a 1:14 ratio (35 grams of coffee for 500 grams/18 oz of water).
  • If you make pour-over coffee at home but only have a low-grade grinder, stick to a medium grind setting and a 1:15 ratio.
  • If you’re a pro home barista with a high-end grinder and get your coffee beans from a specialty coffee roaster, you can’t go wrong experimenting with a broader ratio like 1:16 or 1:17.

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