Why does my coffee taste bitter?

Come banish bitter brews with us as we ask the key question: why does my coffee taste bitter? And how do I solve it?


Ask a coffee hater why they don’t like joe, and you’ll probably get something along the lines of “it’s just too bitter….”

Brewed/ground/bought incorrectly, this can be 100% true. Yup, our lovely coffee can taste bitter, burnt and utterly yucky. But it doesn’t need to be – you know how good coffee can be! So, let’s solve all those bitterness bothers and find out what causes bitter coffee. And, more importantly, how to fix it.


Pink coffee mug on table with stack of magazines


Just a smidgen, please

But let’s not say bye-bye to bitterness altogether. Good coffee needs a little bitterness to help create a well-rounded, flavourful brew. You just don’t want it as the main player. Think part of the ensemble rather than leading light. A well-brewed cup of speciality coffee will taste sweet and complex; packed with flavour and well-balanced by a HINT (no more) of natural bitterness.

Got more than that HINT? Brew blowing your head off with its ugly bitterness? No fear. We’re here with five simple reasons why your coffee might taste bitter all of a sudden.


Pressing down on AeroPress over an orange mug


Brewing for too long

You make a cup of coffee. And then the doorbell rings. Then the dog yaps. Then the phone goes. Then…

*ten minutes pass*

…and now you pour yourself a lovely cup. Only it’s not so lovely. It tastes a tad too strong and rather bitter. This is because your coffee has brewed for too long and started to over-extract. Coffee compounds each extract at different rates. Flavour and aroma extract first, with caffeine compounds being the last ones to jiggle their way out. Of those flavour compounds, fruit-like acidity extracts first, followed by sweetness, and then finally bitterness.

Therefore, leaving your coffee to brew for a short time will result in a brighter, fruitier coffee. Leave it for a bit longer, and your brew will pack more punch.

So, one of the easiest ways you can try to fix bitter coffee is to shorten the brew time by a small amount each time. Try shaving 30 seconds or so from the brew time and take a sip… any better?


Pouring coffee from a cafetiere into a blue mug


Scalding your coffee with hot water

Coffee has a sensitive soul, bless it. If you are wondering why your coffee tastes bad, it could be because your water is too hot. Home kettles boil water to 100°C, but the ideal temperature for making coffee is 92° to 96°C. Scalding your lovely coffee with fiery-hot water will cause the compounds to extract too early and result in a bitter-tasting cup. If your water is so hot it’s still bubbling, this can also agitate the coffee and lead to irregular extraction. Which is never, ever going to give you a balanced cup.

How do we solve this? Investing in a quality thermometer or infrared device is the best way to get the temp spot on. Not fancying the tech? Try leaving your kettle to cool for around 30 seconds before you start brewing


Pouring water from swan neck kettle into v60 brewer


Grinding gone wrong

Grind size is important when it comes to coffee brewing. Make or break kinda stuff. Get the wrong grind size and – poof – lovely coffee suddenly tastes bad. So, if you grind your beans at home and find that your coffee is tasting bitter all of a sudden, we guess it might be down to the grind size.

Grinding too finely makes it difficult for the water to find the gaps. Fine grounds pack tightly together like sand, creating a compact wedge water struggles to get through. The result? The water spends way too long in contact with the grounds. Water and coffee are friends, but it’s a short-term thing. Your water’s had enough after a few minutes, for sure. So, if your cup has a bitter edge, try grinding slightly coarser. This will speed up the brew time and make it easier for the water to trickle down through the grounds.

Prefer fresh pre-ground coffee? We ground all our single-origin beans on the day of dispatch and grind them for your chosen brew device. AeroPress, filter, cafetiere or stovetop – just select your device and look forward to perfectly ground Two Chimps coffee popping on your doormat! Definitely better than bills.



Coffee beans pouring into Two Chimps coffee tin


Grubby equipment

Spring cleaning needs to be a year-round thing for us coffee lovers. If your coffee is tasting bad, it could be down to residue lingering in your coffee device. Dirty equipment can cause coffee residue and oils to build up and give future cups a bitter taste. It’s especially important to keep home espresso makers clean as leftover coffee can cause funny smells, bad tastes and blockages… and potentially a broken machine. Coffee shop owners should clean their coffee maker each day, but home brewers can be a little more relaxed and treat their espresso machine to a bath (not literally) once a fortnight.

Stovetop lover? Things are a little different for you. Bialetti (the original Moka pot makers) don’t recommend using strong detergent to clean aluminium Moka pots because it can irritate the metal and alter the flavour of future coffees. It’s alright, however, to use a mild washing up liquid on stainless steel Moka pots.

Washing your Bialetti under hot running water will be sufficient for daily use, while you can use natural products like white wine vinegar and bicarbonate of soda to give it a deep clean (that won’t leave you with off-tasting coffee) when needed.


Espresso machine in Two Chimps roastery


Using poor quality coffee (please don’t)

No matter how pristinely you keep your coffee maker or how perfectly you grind your beans, little can salvage low-quality beans. Commodity coffee (the stuff that finds its way into some instant pots and chain café cups) is often made with robusta coffee beans. Robusta is a poorer grade of coffee and grows at low altitudes, where there are lots of pesky pests. The robusta plants have adapted to have high caffeine contents because caffeine acts as an insect repellant. Caffeine is bitter, meaning that brews made with, or partly with, robusta beans are much bitterer in taste.


coffee cherries drying


Another thing to bear in mind is how the growers harvest your coffee. Low-grade commodity coffee is usually strip-picked. This gives us a not-so-merry medley of ripe, over-ripe and bitter-tasting under-ripe beans. Think of unripe fruits – they don’t taste nice, do they? So include a bucketload of under-ripe beans in your brew and you’re not going to get something that’s naturally sweet. Commodity coffee roasters then have to over-roast their bitter beans to hide the bad flavours. And what does this over-roasting give you? Yep, more bitter, burnt flavour. Not nice.

The solution is simple. The simplest there is. Just purchase your beans from an indie coffee roaster like Two Chimps. We only source the finest speciality arabica beans and create bespoke roasting recipes to bring out all the lovely natural flavours. It’s the best step you can take to a definitely-not-too-bitter brew. Take a sip and see!


bowl of red coffee cherries


Perfectly balanced brew incoming… head to the shop to see the full range!


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