Why does my coffee taste bitter?
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Bitter coffee is one of the most common complaints people have about brewing at home. And the frustrating part is that it's almost never the coffee's fault.
Bitterness in coffee usually means something went wrong in the brewing process — not in the bag. Here are the three most likely culprits, and how to fix each one.
1. YOUR GRIND IS TOO FINE
This is the most common cause of bitter coffee, and it's easy to overlook because finer always feels more "serious" somehow. More surface area, more flavour — right?
Not quite. When the grind is too fine, the water moves through the coffee too slowly and extracts too much. The pleasant sweetness and acidity come out first; the bitterness comes out last. A grind that's too fine gives you all of it, including the parts you don't want.
Fix it: Make the grind slightly coarser. On most grinders, that means moving one or two steps in the coarser direction. Brew again. Taste. You'll notice the difference immediately.
2. YOUR WATER IS TOO HOT
Boiling water is great for pasta. For coffee, it's too aggressive. Water at 100°C extracts compounds from the coffee extremely fast, including the bitter ones you'd rather leave behind.
The ideal temperature for most brewing methods is between 90°C and 96°C. That's just off the boil — so if you're using a kettle, let it sit for 30 to 45 seconds after it clicks off before you pour.
Fix it: Let your water cool slightly before brewing. If you have a temperature-controlled kettle, set it to 93°C. That single change can noticeably improve the taste.
3. YOU'RE BREWING TO LONG
Every brewing method has a rough time window. Go beyond it, and you extract past the point of balance.
For a V60 or filter, that's around 3 to 4 minutes total. For a French press, 4 minutes is the standard — after that, the grounds keep sitting in the water and the bitterness builds. For espresso, a shot that runs too long (over 30 seconds) will taste sharp and hollow.
Fix it: Time your brews. It takes five seconds and makes a real difference.
A NOTE ON THE COFFEE ITSELF
Some coffees are more bitter than others by nature — darker roasts, for example, have more of the compounds that read as bitter on the palate. If you're consistently getting bitterness even with good technique, it might be worth trying a lighter roast.
Lighter roasted coffees tend to taste brighter and more acidic, with more distinct flavour — fruit, citrus, florals. Less of the heavy, roasted character that can tip into bitterness.
Bitterness in coffee isn't inevitable. It's usually a sign that something small is off — and small fixes are exactly what's needed.
One more thing worth mentioning: technique only gets you so far if the coffee itself isn't working with you. A lighter roast gives you more to work with — more clarity, more sweetness, less of that heavy bitterness that's hard to dial out. Our Ethiopian Filter is a good place to start. Clean, bright, and very forgiving once your brew is dialled in.