Why Does My Coffee Taste Bitter? (And 6 Ways To Balance the Flavor)

Until a few years ago, my coffee routine was a work in progress. I had to experiment with different coffee beans, grind sizes, and water temperatures until I finally landed on the perfect preparation of a creamy latte (at least, perfect in my opinion). But throughout this process, I found myself asking the same question: “Why does my coffee always taste bitter?” My beans were described on their bag as having flavor notes of fruit, caramel, or chocolate — yet each sip was still sour. In search of answers, I spoke to a few coffee experts, who told me exactly how to brew a cup of java that turns out much tastier.

Why Your Coffee Tastes Bitter

The answer to this question starts with the science of coffee beans. “Caffeine and trigonelline, which are present in brewed coffee, contribute up to 10 to 30 percent and one percent of coffee bitterness, respectively,” says medical toxicologist Kelly Johnson-Arbor, MD. “But there are other compounds present in coffee that add to its bitter taste (decaffeinated coffee also tastes bitter, so it’s not just the caffeine that does this). [These] are compounds that are generated during the roasting process of coffee beans, such as furfuryl alcohol and diketopiperazines.”

So, roasted coffee is naturally acidic and sharp in flavor. However, the way you prepare it can heighten its unpleasant taste — hindering the coffee’s sweet, nutty, and fruity notes. Tom Saxon, co-founder of Batch Coffee, says one of four factors (or a combination of them) is likely to blame for your bitter cup:

• Darker roasts. The roast profile has a huge impact on the overall taste of coffee, and in turn, the bitterness. Generally speaking, the darker the roast, the more bitter-tasting the coffee will be. Very similar to burnt toast, the coffee beans start to turn black and produce harsh-tasting carbon. 
• Older coffee beans. Beans grow more bitter with age. This is because they’ve had more exposure to oxygen, which breaks down complex compounds.
• Too much time between grinding and brewing. If you don’t brew your coffee immediately after grinding it, the coffee grounds expand and their surface area increases. This gives the oxygen surrounding the coffee grounds more space and time to develop bitter-tasting compounds. 
• Additional variables. Sometimes your materials and your method don’t match, and the result is a bitter taste. “Materials” include grind size, brew ratio, water temperature, and water pressure. “Methods” include drip, pour over, instant, and more. For example, if your coffee grounds are too fine for a French press, the brew will be over-extracted, which produces a bitter cup. 

Nunzio Ross, founder and CEO of Majesty Coffee, adds that a dirty coffee machine can affect the drink’s taste as well. “Coffee oils can block the machine’s net showers and group head assembly, which causes uneven extraction and adds more bitter flavors,” he says.

How to Make Coffee Taste Smoother

Despite the many factors affecting coffee’s flavor, it’s easy to brew a smoother-tasting cup at home if you know the right steps to follow. Celeste Gucanac, owner of Mobjack Bay Coffee Roasters, shares these simple suggestions for using a clean coffee machine to produce a delicious cup:

• Start with high-quality coffee that hasn’t been sitting on the shelf for weeks. (Try offerings from smaller roasters such as Mobjack Bay Coffee and Amor Perfecto.)
• Make sure your beans are at the proper grind level for your brewing method.
• Use the correct measurements. Gucanac calls 60 grams of ground coffee to one liter of water the “golden ratio.”
• Brew the coffee using water set between 195 and 205 degrees Fahrenheit.
• Apply the correct steep time for your brewing method.

These tips deliver a morning latte or French press coffee that’s rich and full-flavored without excess sharpness. Think it sounds too good to be true? Take it from Jovana Durovic, editor-in-chief at HomeGrounds.co, who offers a final word: “Brewing coffee is an art — treat it with patience and care, and deliciousness will often follow.”