Burnt coffee or “dirty water”: how to avoid these two mistakes?

I maestri della tostatura media
Tazzina di caffè estratto con la moka e sullo sfondo si vedono dei chicchi di caffè interi
The coffees that I generally find in bars or buy at the supermarket have a very strong and unpleasant taste : they taste burnt and are very bitter.

Other times, however, the drink is not extracted correctly from the ground and it really looks like “dirty water”.

What do these two errors depend on and how to avoid them?

Let’s find out together in this article!

What causes the strong bitterness of coffee?

Now I’ll surprise you: coffee is not bitter! Don’t you believe it? I’ll show you!

Ok, fine, coffee is bitter by its nature, due to the roasting process and the presence of caffeine.

This substance in fact if taken alone is really very bitter. This is why Robusta is more bitter than Arabica, precisely because it contains twice as much caffeine.

But a quality coffee should never be excessively bitter! On the contrary, it must leave room for the fresher and more acidic notes of citrus or red fruits, as well as sweet hints of chocolate and ripe fruit.

The bitterness must be soft and delicate and never preponderant over the other tastes.

So why is the coffee I usually find around so bitter?

Because most Italian roasters dark roast, i.e. they cook the bean a lot, until it turns black and then burns.

A bit like pizza or bread in the oven: when they turn black they are burnt.

When we get to toast the coffee too much, it becomes unpleasantly bitter in the cup.

This is why we at Caffè Ernani have chosen the Medium Roasting, perfect for giving cream and body to an espresso, capable of maximizing all the natural aromas contained in the carefully selected and flawless raw beans, without ever making the drink too bitter.
Other reasons why coffee becomes bitter, with an empyreumatic aftertaste, i.e. burnt, are:
  • A water or instrument temperature that is too high. If this exceeds 100°C, the ground burns, bringing bitterness to the cup;
  • Unclean tools. This is because the residues of exhausted coffee, rich in oils and fats, once they come into contact with oxygen begin to oxidize, giving the drink hints of mould, tar, ash, stale, rancid, etc.;
  • The presence of chlorine in the water, for this reason it is advisable to always use filtered or bottled water;
  • The type of tool chosen for the extraction. For example, coffee in a moka is more bitter than coffee extracted with paper filter methods, but these are in turn less intense and concentrated than an espresso;
  • Finally, an over-extracted drink is more bitter than one prepared correctly. By over-extraction we mean that we extracted more than we needed from our ground brick. It happens when the coffee is ground too fine, consequently the water has difficulty passing through the grains and therefore remains in contact with the ground for a long time. Being the liquid at high temperatures and continuing to extract other substances from the ground itself, it burns it, bringing bitterness to the cup.

Grinding is in fact essential to obtain a good coffee. It is useless to buy a quality one if you don’t then adjust the size of the ad hoc for that instrument in that given period of time. A good coffee cannot come out, despite the quality of the raw material. Read all about grinding here!

This is why we at Ernani have given so many grinding options for our products:
  • Turkish
  • Expressed Extracted
  • Mocha pot
  • Neapolitan
  • Aeropress and Syphon
  • V60, Chemex and Clever
  • Cold Brew and French Press
So choose the perfect coffee taste for you and then the format that suits your instrument!

If you have any doubts about which coffee to choose, take the test for “Your blend”!

When is a coffee defined as “dirty water”? Contrary to what we have seen so far, coffee can also be flat, tasteless, sour, acrid and astringent. In this case we call it “dirty water”.

* Astringent = occurs when we eat an unripe banana, raw artichokes or unripe persimmons. It is a dry sensation of the palate along with an unpleasant grit when the tongue is swiped over the palate.

What causes the failure and low intensity of a coffee?
  • From the wrong roasting: if the roasting lasts too long and with low temperatures, one stumbles over a defect called Baking, i.e. boiled coffee, precisely because the incorrect roasting has made it flat, without aromas and with an unlovable taste;
  • From under-extraction of the beverage, i.e. when less is extracted than what should be extracted. Unlike over-extraction, the ground coffee is too large and therefore the water escapes without having time to infuse with the ground coffee and bring oils, lipids and aromatic notes into the cup.

Check for example at the bar: if the barista serves you coffee in 6/10 seconds, the drink will certainly be under-extracted and therefore unpleasant and flat.

But let’s get one thing straight!

Very often when we talk about watered down coffees we immediately think of the classic American “drinks”, rather than a badly extracted drink.

But is not so!

Real American coffee, not our espresso diluted with hot water, should actually be called filter coffee, precisely because a paper or metal filter is used, which supports a certain amount of ground coffee, passed through by a certain amount of percolation water.

These are all complicated words to actually describe a simple preparation.

See how to make it in the video below!

The resulting drink is certainly less concentrated and creamy than an espresso, but at the same time it has no bitterness, resulting in a very aromatic, sweet, sour and really tasty coffee.
We won’t see the cream in the cup, but we will feel an explosion of perfumes on our palate!

So no, filter coffee isn’t dirty water, it’s just a method of preparing the drink other than espresso!

Marketing, E-commerce e Social Media Manager
Coffee Lover


Martina Mazzoleni

Marketing, E-commerce e Social Media Manager Coffee Lover

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