What to Do About Bitter Coffee: Why Coffee Tastes Bitter and How to Fix It

Coffee is meant to be a delightful sensory experience with notes of chocolate, caramel, berries, and more dancing across your palate. But sometimes, all you taste is bitterness. Overly bitter coffee can leave a bad taste in your mouth (literally). But it doesn’t have to be that way.

With just a little understanding of the science behind bitter coffee, you can banish the bitterness for good. In this guide, I’ll walk through the main reasons your coffee tastes bitter, and provide actionable tips to help you brew a deliciously balanced cup every time.

Why Coffee Tastes Bitter

Before we can fix bitter coffee, we need to understand why it tastes bitter in the first place. Although it’s complicated, the primary underlying reason is overextraction.

Overextraction is when too many soluble compounds are drawn out of the coffee grounds during brewing. This results in a brew that is unbalanced, muted, and bitter.

There are several factors that can lead to overextraction and overall bitter coffee, which I’ll discuss in the following sections.

Type of Coffee Beans

The type of coffee beans you use has a big impact on bitterness. Arabica and robusta are the two main species of coffee plants used for commercial coffee production, accounting for around 70% and 30% of the world’s coffee production, respectively.

Arabica coffee naturally has about half the bitterness of robusta. The reason lies in their chemical composition. Arabica has about 1.5% caffeine content, while robusta has a whopping 2.7% to 4.0%. Caffeine is one of the main compounds that contributes bitterness to coffee.

In addition, robusta has higher levels of chlorogenic acids. These organic acids have a bitter, astringent taste. Robusta also tends to lack the natural sweetness and fruitiness of arabica due to less sugar content.

For a less bitter brew, choose arabica coffee whenever possible. Opt for beans labeled as “100% arabica”. The beans will taste cleaner and sweeter, with chocolate and caramel notes rather than harsh bitterness.

If you’re stuck with robusta (like in grocery store canned coffee), try adding milk or sugar to mask the bitterness.

Coffee Origin

The country and region a coffee is from affects its flavor profile, including the bitterness. Coffee grown at high altitudes with rich volcanic soil tends to be naturally sweet coffee with a pleasant acidity. Meanwhile, beans grown in less optimal conditions take on more bitter, earthy qualities because they ripen too quickly and develop more of those bitter coffee compounds.

Some coffee origins known for balanced, fruity flavors include:

Colombian coffee
Kenyan coffee
Costa Rican coffee
Ethiopian coffee
Guatemalan coffee

Processing method also affects bitterness. The washed process leads to a bean that is clean and bright tasting. Natural and honey processing highlight fruitiness but can amplify bitterness if not done properly.

Stick to reputable specialty roasters that source high quality beans and pay close attention to the method the farmers use for processing. This results in naturally sweet coffees that limit bitterness.

You can also choose your coffee based on your brewing method for the ideal flavor profile. For example, choosing a light roast coffee for pour over would yield an entirely different set of flavors than if you used that same coffee in a French press. Pour over cones like the V60 and Chemex brewers tend to highlight bright acidity and fruity sweetness, whereas using that coffee in a French press would highlight less of the fruitiness and more of the nutty or chocolaty notes.

If you typically brew an Americano rather than regular coffee and find it to be too bitter, try a manual brewing method like pour over or Chemex, which highlight lighter and brighter flavors than you’d find in espresso.

Degree of Roast

Lighter roasts are less bitter than dark roasts. Why? It comes down to chemical changes during roasting.

In the middle stages of roasting, sugars caramelize, which adds sweetness to your coffee. As the roast progresses, these sugars break down. More extended roasting also causes the chlorogenic acids to degrade into quinides and lactones, both of which are compounds with harsh, bitter flavors.

With a dark roast, you completely lose the origin character of the bean. At that point, you’re just tasting roast characteristics. Eventually, you get to the point where you’re denaturing proteins in the beans and breaking down the cell walls, which will lead to a burnt, bitter flavor in your cup.

For minimal bitterness, go with a light or medium light roast to preserve the coffee’s inherent fruitiness and sweetness.

Grind Size

The grind size you choose directly affects extraction and bitterness during brewing. Finer grinds are more likely to lead to overextraction, while coarser grinds are more likely to underextract. You really need to match your grind size to your brewing method and then adjust based on taste.

Use a medium-fine grind for automatic drip and pour over. This strikes the right balance to extract flavor without excessive bitterness. Go a bit coarser for cold brew and French press to prevent overextraction.

Make sure you’re using a quality burr grinder, too, not an inconsistent blade grinder. Uneven particle sizes from blade grinding make both under and overextraction happen in the same brew, which leads to bitterness and other off flavors.

Always adjust your grind based on your brewing method and coffee origin. Lighter roasts require a slightly finer grind than darker roasts. Compensate accordingly to achieve a balanced extraction, and remember that coffee acidity can become too much if you go too far in the opposite direction and cause underextraction.

Dose of Coffee Grounds

The dose—or amount of coffee grounds you use to brew—determines the strength of your brew. Too many grounds can lead to overextraction and an unpleasant bitterness in your coffee.

Start with the standard ratio for your brew method:

Drip machine: 17:1 water to coffee ratio by weight
Pour over: 14:1 to 20:1 water to coffee ratio by weight
Chemex: 16:1 water to coffee ratio by weight
French press: 15:1 to 17:1 water to coffee ratio by weight
Cold brew: 6:1 to 8:1 water to coffee ratio by weight

From there, adjust to taste. Your taste buds are the ultimate judge. Increase the grounds for a stronger coffee, or decrease for weaker. Just be mindful that more grounds increase the risk of bitterness.

For cold brew specifically, you usually won’t experience much bitterness because of the low water temperature. However, using a ratio that’s too high can be perceived as bitter, so dialing in by weight is still best for consistency.

Water Quality

Hard water makes coffee taste salty and bitter. The minerals present interact with coffee compounds to suppress sweetness and accentuate harsh flavors.

Magnesium and calcium are the main culprits. Their concentration is measured by water hardness level. The higher the level, the more magnesium and calcium present:

0-60 ppm: Soft
61-120 ppm: Moderately Hard
121-180 ppm: Hard
180+ ppm: Very Hard

If you have hard water, use filtered water for brewing whenever possible. A simple carbon filter removes chlorine but doesn’t affect minerals. Opt for a speciality brewing filter to reduce water hardness and bitterness.

If you have a water softener, though, it can introduce some salt into your water, which can promote bitter flavor a bit. In that case, softening and then filtering your water should do the trick.

Reverse osmosis filters and distilled water remove all minerals. They can make coffee taste flat and dull, though. Add a pinch of Epsom or calcium chloride salts to restore some beneficial minerals.

Start with quality water so your coffee’s natural flavors shine instead of harsh bitterness.

Brewing Method

Brew method affects contact time between water and coffee, as well as agitation and water temperature, all of which can change the rate of extraction and, as a consequence, the bitterness you get in your coffee.

For example, espresso has brief contact, only 20 to 30 seconds. This limits its bitterness. But high pressure and hot water also increase the rate of extraction. Coarsen your grind size, increase pressure, or reduce water temperature a bit if you’re getting too much bitterness.

Pour over falls in the middle in terms of extraction rate, with three to four minutes of contact time. It relies entirely on gravity, not pressure, for extraction. Maintain a consistent pour and wet all grounds evenly to extract sweetness without excess bitterness.

Cold brew involves long exposure—12 to 24 hours. While this would normally bring out bitterness that overpowers other flavors, the low water temperature virtually eliminates any bitterness. Choose the right roast for cold brew, and you’re all but guaranteed to get bitter-free, smooth, and balanced coffee.

Something like a moka pot that’s prone to overextraction is going to produce bitterness in your cup naturally, so more tinkering with grind size will be needed to reduce bitterness.

Try out different brew methods to find your flavor preferences. Just keep bitterness risk in mind and adjust your dose, grind size, and timing accordingly.

Water Temperature

Hotter water extracts faster and can scorch coffee compounds. Colder water extracts much more slowly. The perfect temperature for most brewing methods is between 195 and 205 degrees (F), with cold brew being the only real exception at room temperature or fridge temperature.

It’s often tempting to use boiling water to brew your coffee because it’s easy and doesn’t require any additional equipment. However, I recommend investing in a kettle with a thermometer that lets you dial in the ideal temperature to avoid bitter coffee. Dialing in the optimal temperature for your brew method brings out sweetness and balances bitterness.

Brew Time

Contact time between coffee and water determines extraction. More time equals more extraction. While flavor extracts quickly, bitter compounds in coffee extract more slowly. Plus, a lot of bitterness can come from the cell walls of the plant breaking down after long exposure to heat. As such, a brew time that’s too long accentuates bitter notes.

Follow general brew time guidelines based on method:

Espresso: 20 to 30 seconds
Aeropress: 2 to 3 minutes
Drip machine: 4 to 6 minutes
Pour over: 3 to 4 minutes
French press: 3 to 4 minutes
Cold brew: 12 to 24 hours

If your coffee starts tasting bitter and overextracted, cut the brewing short. Adjusting brew time is an easy way to balance sweetness against bitterness.

Coffee Freshness

Stale coffee tastes flat and bitter. Freshness is key for balanced flavor. And…I hate to be the one to burst your bubble, but most pre-ground coffee is going to taste bitter, especially if you buy something like Folgers or Maxwell House that’s ground weeks or months before it hits the shelves.

I recommend you only buy roasted coffee beans you intend to consume within 2 weeks. Whole beans stay fresh longer than pre-ground. And ideally, you’ll find a “roasted on” date on the package that confirms the roasting took place no longer than 2 or 3 weeks before you buy it. Roasted coffee reaches peak flavor after about 5 to 7 days, so that timeline is even better.

Store your beans in an airtight container in a cool, dark place. Light, heat and air degrade freshness quickly.

Grind beans right before brewing—no more than 15 minutes prior. I recommend avoiding pre-ground coffee beyond a day, even if it’s sealed. The massive surface area exposed to oxygen destroys freshness and amps up bitterness.

If you won’t finish the beans within 2 weeks, freeze a portion in an airtight bag. Thaw before grinding and brewing.

Prioritize fresh, local roasts whenever possible. Support your local roasters who provide coffee at peak freshness.

With proper storage and grinding, you can all but rid of nasty bitterness in your coffee, even if you don’t take any other advice in this article.

Brewing Equipment Maintenance

Failure to clean your brewing equipment properly can lead to the buildup of rancid oils and coffee residue, which then impart bitter, unpleasant flavors into your coffee.

Follow the manufacturer’s instructions for cleaning your coffee machine. Vinegar or citric acid solutions help remove buildup, or you can buy coffee grinder cleaning tabs and coffee maker cleaning solutions to help.

For French presses and pour over devices, disassemble all parts. Give them a thorough hand wash with dish soap and hot water. Never use abrasive scrubbers that can scratch surfaces. Soak metal mesh filters occasionally in a solution of hot water and baking soda. Rinse thoroughly afterwards.

Grinders require frequent cleaning as well. Wipe the burrs and container down with a dry cloth to remove coffee oils. Grind cheap rice periodically to absorb residual grounds and oils.

Proper cleaning removes contamination that damages flavor. Your reward is pure, freshly ground coffee taste without excessive bitterness.

How Does Caffeine Content Affect Bitterness in Coffee?

As mentioned earlier, caffeine is one of the central compounds that gives coffee its bitter taste. The higher the caffeine content, the more intense bitterness becomes.

While beneficial for energy, caffeine triggers a bitter taste receptor called hTAS2R43. The more caffeine present, the more hTAS2R43 receptors are activated. Your brain perceives this as potent bitterness.

Robusta beans contain almost double the caffeine of arabica—2.7% to 4% as opposed to around 1.5%. As a result, robusta tastes far more bitter. The higher caffeine content overly stimulates your bitter taste receptors.

If you consume caffeine in moderation, you become less sensitive to bitterness over time. But excessive intake keeps your bitterness receptors highly active and responsive.

When shopping for beans, check the roaster’s caffeine information. Seek out 100% arabica beans when possible for lower bitterness. Consuming coffee with food also helps mediate bitterness perception.

What Is Bitterness Threshold?

Bitterness threshold refers to the point where a person perceives bitterness in a food or drink. It’s tied to the number of bitter taste receptors (TAS2Rs) on their tongue. People with more receptors detect bitterness at lower levels.

Each individual has a unique bitterness threshold influenced by the following factors:

Number of taste buds
Density of bitter taste receptors
Signal strength to the brain
Presence of modulating proteins

A compound must reach a certain concentration before it activates your TAS2R bitter receptors. This concentration threshold varies person to person.

When making coffee, don’t go just by a set recipe or brew chart. Your bitterness threshold likely differs from the average. Experiment to find the brew parameter sweet spot—origin, dose, grind size, time, etc.—where you achieve balanced flavor without crossing your personal bitterness threshold. It takes trial and error to dial in coffee you truly enjoy.

What Should Coffee Taste Like?

When brewed properly, coffee is an intricate bundle of flavors. Roasting and brewing transform the chemical compounds in beans to bring out specific tastes:

Acidity: Bright, tangy tartness like citrus fruits. Acids balance and enhance other flavors.
Sweetness: Sugars in the bean caramelize during roasting. They impart a smooth, subtle sweetness.
Fruitiness: Coffees inherit flavors like berries, apple, and stone fruit from their origin. Processing enhances fruity notes.
Spiciness: Dry spice flavors like pepper, nutmeg, and cinnamon. Result of bean compounds reacting during roasting.
Chocolate: Beans from certain origins yield cocoa and dark chocolate flavors when roasted.
Floral: Honeysuckle, orange blossom and other floral notes shine through in some beans.
Wine-like: Some coffees have a complex fruit-driven profile reminiscent of red wine.
Earthiness: Savory, grain-like flavors from compounds in the soil. Most notable in Sumatran coffee.

No single coffee will have all these flavors. But there should be a vibrant orchestra of tastes playing on your palate, not just unilateral bitterness.

If bitterness is the only flavor coming through, your coffee is likely stale, burnt, overextracted, or some combination of the three. Dial in your brewing to uncover the bean’s true flavors, or consider choosing a different origin and roast profile.

How to Fix Bitter Coffee

Don’t tolerate overly bitter coffee—fix it! Here are my top tips for banishing bitterness and bringing out coffee’s inherent flavor nuances:

Add milk or cream: Dairy fats coat your tongue and mask bitterness. Adding a splash of milk or cream is an easy fix if your current cup is too bitter. Milk is also naturally a little sweet, and the sugars can balance out some of the bitterness.
Use less coffee: Excess coffee concentrate amplifies bitterness. Try reducing your dose by 10% or more.
Choose lighter roasts: Dark roasts destroy coffee’s sweetness and acidity. Medium to light roasts have a fruitier, more balanced profile with less bitterness and burnt flavors.
Switch brew methods: Quick methods like espresso limit extraction of bitter compounds. Or try cold brewing for low-and-slow flavor.
Adjust grind size: Medium-fine is ideal for most automatic brewers. Coarser grinds prevent overextraction but can sacrifice flavor at some point.
Control brew time: Stop early if your coffee starts tasting astringent or bitter. Shorter time prevents overextraction of bitter compounds.
Pick better beans: Seek out 100% arabica beans from reputable specialty roasters. Higher quality means sweeter flavor.
Use pure water: Filter your water to remove minerals that dampen sweetness and amplify bitterness.
Clean equipment: Change filters and descale machines regularly. Remove rancid coffee oils that ruin flavor.
Add finishing flavors: A sprinkle of cinnamon, raw sugar, or cocoa powder helps offset bitterness after brewing.

At the end of the day, your preferences reign. Experiment with different beans, roasts, ratios and methods until you concoct a personalized brew free of excessive bitterness.

Wrapping Up: Say Goodbye to Bitter Brews

Bitterness doesn’t have to dominate your coffee drinking experience. With a little troubleshooting and a few easy tweaks, you can transform your morning bitter brew into a smooth, nuanced cup of joe.

Prevent overextraction by dialing in dose, grind size, time, temperature, and other key factors. Choose high quality arabica beans for optimal sweetness and acidity.

If you overshoot and end up with a bitter cup, curb the harshness by adding milk or switching up your next brew. Most importantly, have fun playing around until you create your ideal personalized cup!

Frequently Asked Questions

Why does dark roast coffee taste more bitter than light roast?

Dark roasts are more likely to taste bitter because roasting coffee beans for longer periods of time breaks down the natural sugars that provide sweetness. Dark roasting also degrades the coffee’s chlorogenic acids into compounds that have a harsh, bitter flavor. Light roasts preserve more of the bean’s inherent sweetness and fruitiness for a more balanced, less bitter taste.

Can grinding coffee beans too fine make coffee taste bitter?

Yes, an overly fine coffee grind can make coffee taste bitter and overextracted. Finely ground coffee has more surface area exposed, which allows the hot water to extract more compounds from the grinds. This includes bitter elements like caffeine. A medium-fine grind is best for most auto-drip machines. You will need to go coarser for methods like French press. Adjust your grind to optimize extraction without excessive bitterness.

Will adding cream and sugar mask bitterness in coffee?

Adding dairy products like cream, milk, or sweeteners like sugar does help mask bitterness in coffee. The fat in milk and cream coats your taste buds, blocking reception of bitter flavors. The sugars in dairy will also balance out some of the bitterness you’re tasting. Straight sugar may overwhelm bitterness with sweetness. However, adding cream and sugar should just be a quick fix for a overextracted cup. For long term solutions, improve brewing methods to bring out the coffee’s inherent flavors.

Why is cold brew coffee less bitter than hot brewed?

Cold brew coffee is naturally lower in bitterness because the cold water extraction process only pulls out the sweet, more soluble elements from the coffee grounds. Immersing grounds in room temperature or cool water for 12 to 24 hours avoids extracting harsh bitter compounds. The slow steep time and low temperature of cold brew prevent overextraction leading to balanced, smoother flavor.