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Have you ever wondered why some coffees have that bitter taste? Well to remove the bitterness would be to remove the coffee because all coffee is bitter regardless if it’s strong or mild.  Let’s face it, coffee is a bitter beverage. So, why are you drinking bitter coffee? ” In this post we’ll explain the different bitter flavours and how they come about. We will also identify factors that contribute to bitterness and steps you can take to reduce the bitterness and ensure your coffee hits the sweet spot.

Good Bitterness – Does it really exist?

Yes it does. I have been judging coffee for the past 20 years with the Sydney Royal Fine Food Show which is part the prestigious Royal Agricultural Society of NSW. And Good bitterness is an attribute that we look for in coffee. Remember coffee is a bitter beverage and it’s the bitterness that gives coffee it’s unique taste. What we look for in terms of bitterness is a bitter-sweet balance between acidity, earthiness and carbony.

Before we go through the factors that help reduce the bitterness in coffee we need to get you to know which bitterness you prefer.

Is Caffeine bitter?

Yes, pure caffeine is bitter. However, according to the article published 08 June 2026 “Why doesn’t coffee taste like caffeine” by analytica-world.com the caffeine in a cup of coffee doesn’t contribute significantly to the coffee’s bitterness. Interestingly the Journal of Agricultural and Food Chemistry explains that the answer may lie within interactions between caffeine and other coffee molecules called melanoidins that are produced during the roasting process helping suppress the caffeine bitterness.

Why are some coffees bitter and others aren’t?

Our family has been sourcing, roasting and blending coffee for 4 decades. Over this time we have clearly understood how subjective coffee is amongst different people. Many people will define an acidic coffee as being too strong and bitter. Whilst others say that a dark roast is burnt and tastes bitter. Who’s right??? Well, let’s find out.

There’s two main bitter flavours in coffee – Acidic and Carbony

1. Acidic

• Acidity is the tanginess, zest and wine like tanin texture that gives life and character to coffee.
• Arabica coffees from Africa and Central America are renown for their bright fruity like acidity.
• Light to medium roasted coffees display a more prominent acidity.

‘However, if the coffee is too lightly roasted you’ll taste an overwhelming tart/sourness because it has not been developed enough.’

Our family’s expertise ensures we roast all our coffees into what we call the ‘Sweet Spot’. It’s where the magic happens transforming the coffee’s acidity into a well balanced and palatable coffee. So, if your drinking an espresso and you’re finding it too tart/sour to enjoy, then that particular coffee is not for you. And quite frankly an espresso should have an upfront full body, complexity, texture and depth of flavour. You should enjoy it and not struggle to drink all of it.

 2. Carbony

• Carbony as the word implies comes from a more developed darker roasted coffees.
• A medium roast coffee will transform the coffee’s acidity into a sweet rich balanced coffee and also display nutty and chocolatey flavours.
• Carbony flavours develop when sugars and organic compounds are roasted further, creating deeper notes reminiscent of dark chocolate, toasted nuts, and roasted cacao rather than bright fruity acidity.
• Lower perceived acidity allows these richer flavours to dominate the cup, producing a fuller-bodied coffee with a smooth lingering finish.

‘However, if the roast is too dark then yes a very burnt unpleasant bitterness will dominated the cup and the coffee will lack acidity hence complexity, body and texture.’

There is no right or wrong in bitterness. But, the one you prefer is the right bitterness for you. So, in order to work out which bitterness you prefer, you’ll need to taste two contrasting coffees – a slightly acidic against a slightly carbony. A good example is our “Fruity Caramel” Colombian as the lively acidic one against our “Dark Choc” South Bar blend as the slightly carbony one.

What is coffee bitterness

It’s basically when you say “I can’t drink that. It’s got that awful taste.” Coffee bitterness isn’t mainly from the raw beans – it’s created during the roasting process. Scientists identified two key compounds that form as beans are roasted, which cause different types of bitterness. (Sophie L. Rovner accessed 13 April 2026) https://cen.acs.org/articles/85/i38/Tweaking-Coffees-Flavor-Chemistry.html

Two Types of Bitter compounds

1.Chlorogenic Acid Lactones (milder bitterness)

• Formed early during roasting from natural chlorogenic acids in the beans.
• Give coffee smooth, mild bitterness.
• Common in light to medium roasts.

2.Phenylindanes (strong, harsh bitterness)

• Form when roasting continues further and breaks down the lactones.
• Create a strong, sharp, more bitter taste.
• Found mostly in dark roasts.

Key Takeaway

‘The darker the roast, the more the mild bitter compounds turn into stronger ones – this is why dark roast coffee tastes much more bitter than lighter roasts.’

Factors that contribute to coffee bitterness

 

Clean Equipment

• Ensure that your equipment is clean and free of coffee residue build up as this will taint the flavour of your coffee.
• Thoroughly rinse equipment after cleaning with hot water.
• Prime groups in espresso machines with coffee after chemically backflushing.

Water freshness

• Use industry standard water filters to keep your water taint free and ensure the longevity of your equipment.
• Use fresh water each time you brew.
• For home equipment add fresh water more regularly into the tank rather than having it full and allowing it to stagnate.
• With all espresso machines it’s good practice to flush the group and boiler water regularly.

Coffee species – Arabica versus Robusta

• Arabica:  − Very aromatic, great sweetness, complexity, good acidity and length
• Robusta: − Heavy body, bold and earthy, low acidity, chocolate notes

Roasting – light to medium versus Dark roast

• Light roasts: brighter vibrancy, mild body, high acidity, cereal aroma.
• Medium roasts: more complexity, well rounded and balanced, good sweet palatable acidity, enticing fruity/nutty/chocolate aroma.
• Dark roasts: Stronger bold roasty notes, bitter, earthy aroma and flavour, low acidity

Coffee bean origins

• Brazilian, Indian, Honduran, these arabica coffees display smooth chocolaty, malt and marzipan flavours – espresso friendly
• Guatemalan, Colombian provide sweet butterscotch and vibranty nuttiness. Great length medium bodied -plunger/filter friendly
• Ethiopian, Kenyan display sweet fruity flavours with tea like texture – plunger/filter friendly

Freshness

Once a coffee pack is opened, the coffee will start to decline in flavour and develop stale rancid bitter flavours in around 4 weeks . So, it’s best to buy your coffee freshly roasted and once the pack is opened consume it within a month. The interesting thing about coffee is as it starts to stale it loses flavour but doesn’t develop strong pungent odours like off foods. Although you can enjoy coffee within a few days from roasting, the flavour is at it’s optimum in the third week from the roast date. You’ll find that the flavour is more vibrant, sweeter, livelier and has more length.

‘Coffee is best consumed in it’s third week from the roast date.’

• Buy freshly roasted coffee.
• Consume within a month.
• Use resealable bags and press out excess air space.
• Store in specialised air tight containers that remove the excess air space.

Grind texture – Coarse versus Fine

What your tasting in a coffee is the actual dissolved solids of the ground coffee.

• Finely ground coffee has more surface area that is in contact with the hot water and therefore extracts more dissolved solids hence more body.
• Too fine can mute the clarity and acidity of the coffee.
• Coarsely ground coffee extracts faster and hence lacks body, complexity and tastes flat.

However, it does depend on the coffee maker as you would know plunger takes quite a coarse grind similar to coarse table salt.

However, there are grinding parameters especially when it comes to espresso machines.

Brewing temperature

• Espresso machines 90ºC – 94ºC
• filter 94ºC – 96ºC
• Plunger 96ºC

Brewing times – Short versus Long

• The less time the ground coffee is in contact with the hot brewing water, the less amount of dissolved solids are extracted hence less body.
• Longer extraction more dissolved solids hence more body.

Coffee to water ratio

provide some for a variety of coffee makers (explain in the stove top you can’t really adjust dose as it fills slowly and will brew too fast. Whereas the espresso has that instant 9 bar pressure which the hot water fills any air space so fast that it acts likes a piston and presses the hot water through the ground coffee.as a base and explain what happens when you change these ratios  TDS

show photo liquor colours of the varying grind texture relavent to the TDS ie: colour which relates to body. Show with milk too. Same coffee gramage, Fine/med/coarse grind and corresponing colour.

Drinking temperature

A fresh hot cup of coffee constantly changes flavour as it cools. How we perceive the aroma, body, sweetness, complexity, texture and mouthfeel is relative to the temperature.

• Too hot – lacks body, tastes flat and highlights bitter notes.
• Too cool – Thin watery, lacks character and highlights acidity.
• Perfect temperature  45ºC – 55ºC.

Coffee flavor is not static; it changes as temperature affects the volatility of aromatic compounds, the way our taste buds perceive them, and the texture we experience in the mouth.

Ideal beverage temperature regardless if it’s an espresso, filter or plunger coffee is around 45ºC – 55ºC.

and As with any hot liquid or food we’ve been told, let it cool down or you’ll burn your tongue. whether it be coffee, tea or soup, your taste receptors Allowing the coffee to cool slightly gives it a better overall mouthfeel and flavour. In saying, there are peolple who enjoy their coffee very hot.I recall a few times people poping in for coffee beans and when I offer them a coffee they ask for an extra hot coffee. I firstly make them an ideal temperature coffee and ask them how is it. Some politely say “not hot enough” and of coarse I then regrettably make them extra hot one. However, some say “it’s not too bad” and I then ask them “can you notice that that coffee has a fuller taste and more body”. they agree agree and thank me for helping them enjoy their coffee more.             always suggest to the Although some people do prefer their coffee

5 steps in reducing the bitterness in strong coffee

To make a strong without it being bitter is a matter of tweaking the components that contribute to the bitterness in coffee. But, firstly you will need to do a little experimental tasting and workout which . You basically need to identify what you like and don’t like out of the coffee. Deal with one variable at a time.

1. Try a medium to dark roast against a lighter roast

Brew them simultaneously or as quick as possible so that you’re comparing them at the same temperature.

2. Compare a blend of 100% arabica versus an arabica/robusta blend

Here you should be able to taste the earthier heavy boldness of the robusta. What you’ll find is that the 100% arabica blend will have a brighter lively acidity. This will help you understand and determine which bitterness you prefer – acidic or carbony.

3.

Q & A’s

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