Why Does My Coffee Taste Bad 

 January 27, 2019

By  Enda McLarnon

Why Does Coffee Taste Bad - How To Make Sure It Doesn't

There are many reasons why coffee tastes bad and it can be a really frustrating problem. In this article we look at some of the most common problems associated with coffee, and more importantly, how to make sure they never happen to you.

Now we should say right from the outset, that there are a lot of different methods to make coffee. Below we will cover off all of the common brewing methods, and explain where each type of brewing can go horribly wrong.

We have also included a menu just below. That will allow you to pick out the individual method you use to make your coffee. You can click on that link to go straight to that section, rather than read the whole article.

Bad Tasting Instant Coffee

Let's start with the most basic of them all, and that is the good old instant coffee. Instant coffee is also referred to as soluble coffee, coffee powder or coffee crystals.

It is hard to get this wrong in terms of brewing. You add a spoonful of coffee and then hot water. You also have the choice of adding sugar/ sweetener and milk.

So in terms of brewing very little can go wrong as long as you have hot water.

The advantages of using instant coffee is it is easy to use and has a long shelf life.

Instant coffee is made by most coffee brands and those include:

  • Nescafe
  • Maxwell House
  • Lavazza
  • Kenco
  • Douwe Egberts
  • Cafedirect
  • L'OR
  • Percol
  • Starbucks
  • Beanies

Instant coffee starts with the beans which are then roasted and ground. Those grounds are then either freeze dried or spray died. They are then dried and packaged which removes all the moisture from the beans. When we pour water on the instant coffee, it brings the moisture back into the coffee grains.

What most people don't know about instant coffee is that the majority of it is made from a high percentage of Robusta beans.

There are two types of coffee beans which are Arabica and Robusta. Without getting into a lot of detail, Arabica are a much better quality bean, and used in almost every coffee shop.

Instant coffees that use Arabica only will taste better than those that are blended with a mixture of Arabica and Robusta. However those types of coffee will also be a lot more expensive.

The reality is that instant coffee will never taste as good as freshly brewed coffee. That said it is good enough for most people.

Our advice would be is to avoid really cheap coffee as the quality of the beans used will be low. Don't be afraid to experiment with different brands.

bad tasting coffee

Bad Tasting Filter Coffee

In the UK many people still like the taste of their filter coffee. There are a few different ways of making filter style coffees. In this section we will explain the filter machine, and in the next section we explain bad tasting coffee when using a French Press.

Filter Coffee Machine

The most popular method is to own a filter coffee machine, with the traditional glass carafe. We like that style of coffee as well, but sadly this brewing method is the one that is most likely to make bad tasting coffee.

There are quite a number of things that can go wrong here. We have listed those below:

  • The wrong thickness of grind is used
  • The water is not hot enough
  • The filter system is poor
  • The beans are not fresh
  • The keep warm plates are useless
  • Limescale problems

Yes we understand that it a lot of different issues, but with filter coffee machines all of these can come into play. Let's go through these issues one at a time.

Wrong Grind Thickness for Filter Coffee

Filter coffee machines need a medium/coarse grind. It may take a few trial and error attempts to perfect this type of grind. Filter coffee machines use what is called "immersion" to brew the coffee.

This process is where the ground coffee beans are immersed in hot water, and allowed to soak there, before dripping into the carafe.

  • If the grinds are too coarse the water quickly goes through them and you end up with very weak tasting coffee (dish water as some people call it)
  • If the grinds are too fine, then the water can not get through them as it is not pressurised, and the coffee is almost impossible to brew. You also end up with a load of dusty grains in the bottom of your cup

If you buy ground coffee then in most cases it is ground to the right size. However if you buy beans and grind those yourself, then it is vital to get the proper grind.

Water Not Hot Enough

Another common problem with some filter coffee machines is that they do not heat the water to the right temperature. Coffee should never be made using boiling water as that actually burns the grains.

However it should be very close to boiling. Some filter machines, especially the cheaper ones simply don't do that and that will always result in bad tasting cool coffee.

The water and the boiler should be able to heat the water properly.

Poor Filter System

Some of the metal/plastic filters are just very poor quality. They do a very bad job of filtering out the grains and that of course leaves those in the bottom of your cup.

Metal filters are always a better option, but they do need to be properly cleaned out after every brew.

Adding a paper filter can also really help a lot.

Coffee Beans are Not Fresh

Whether you use beans or grounds, you always need to make sure they are fresh. Coffee beans and grains unless stored properly do not have a long shelf life.

Coffee is always best when it is as fresh as it can be. Ideally you should only ever 

Keep Warm Plates

Almost every filter coffee machine has a warming plate. This is the area on the machine where the glass carafe sits to collect the brewed coffee. These plates warm to a certain temperature, and the principle is that once the coffee brews, then this plate will help keep the coffee warm.

Filter coffee always tastes its best when it is first brewed and fresh. Some people may like a second cup and that is why they like this keep warm plate. However the majority of these plates don't really keep the coffee that warm, or they are too hot and end up burning the coffee.

Personally we think these plates are just a bad idea. They are also the feature that gets the most complaints.

Limescale Problems

Over a period of time limescale will start to build up on any part of the machine that is made from metal, and comes into contact with water. There are minerals and impurities in most water supplies, and when they come into contact with metal, then lime can build up.

The harder the water supply the more lime there will be and it varies across the various regions of the UK. There are cleaning tablets which can be used to clean your coffee machine, by using the tablets and then running hot water through the machine.

Some of the better machines will come with an automatic descaling program, but these will always be a little more expensive.

filter coffee tastes bad

Bad Tasting French Press Coffee

The French Press method of brewing coffee remains a popular option in the UK. It is a pretty simple method for brewing strong and aromatic coffee. There are really only a few simple things that can go wrong with this method of coffee brewing. These are:

  • The grind is either too fine or too coarse
  • The water is not hot enough
  • The brew has not been left long enough

Getting the Grind Just Right

Coffee grains for a French Press need to be just right. The ideal grind is classed as a medium/coarse grind. That allows the water to flow through the grains, extract the coffee flavour, and then  brew the coffee.

If the beans are too thin, the water can not get through as there is no water pressure to force it through. It will mean that the brew gets clogged up, and any coffee you may get, will be full of coffee dust.

If the beans are simply too coarse of a grind, then the water passes quickly through, and you get a very weak brew.

It may take you a few tries to get the grind just right for this type of brew. It is worth persevering though.

Water Temperature

Avoid boiling water straight from a kettle. Boil the kettle for sure, but then leave it for about a minute, and then use it. Boiling water can scald the grains. The water needs to be hot but not boiling.

Brew Time

Once you have made the brew, it does take some time to settle. The longer you leave the coffee in the water, then the stronger your coffee will be. However is it is left too long, then it can become bitter.

Bad Tasting Espresso Coffee

This is the most popular coffee made at home by those who really like their coffee, and want an espresso machine in their home. Espresso is as you may know the core ingredient for latte, cappuccino and many other coffee drinks.

If you can master making the perfect espresso, then you will always have great tasting coffee. However there are a few key reasons why your espresso coffee may taste bad. We have listed those below:

  • The wrong grind is used
  • The coffee has not been tampered
  • The water is at the wrong temperature
  • The machine has not been cleaned

Most coffee machines do a very good job of making your espresso. The bean to cup machines are the best, as you simply put the beans in the hopper, push a button, and watch great tasting coffee come out the bottom.

The entire process is automated from beginning to end. These are however the most expensive of machines.

The most popular machines are classed as semi-automatic machines. With these you do the grinding, tamp the grains and put the grains into the portafilter. You then attach that to the group head to brew the coffee.

It is this manual intervention area where the brewing can go wrong. Let's explain that in more detail.

Wrong Grind is Used

For an espresso a very fine grind has to be used. When you get that right, then the water that is pressurised by your machine, can make its way through the finer grains.

If the grain is too thick, the water goes through too fast, and you end up with very weak coffee. The grain type should be a similar consistency to fine beach sand or a powdered sugar.

On the other hand if the grind is too fine, then the the ground coffee will simply block the portafilter. This type of extremely find grind is used only in "Turkish coffee," and that uses a very different brewing method.

Getting the grind right is very important for a good espresso with a proper crema. Our advice is to buy a pre-ground espresso as that will really have the perfect grind. Once you see what that looks like, then you can then grind your beans to this type of grind.

Coffee Not Tampered Properly

Using a tamper to compress your coffee in the portafilter is also very important. May coffee drinkers and coffee experts disagree as to what the best pressure is to tamper your coffee.

Some say it should be high at around 30 lbs of pressure, and others say the ideal tamping pressure is at 8 lbs. For now, don't worry about that too much, as it is better to understand why we do tamper at all.

Why Tamper Coffee in the Portafilter?

First, allow me to explain the purpose of tampering the coffee in the first place.Tamping compresses the grinds into an evenly distributed puck. When the water flows through the coffee grounds, this is referred to as the "extraction process."

During this process, the hot water is forced through the coffee grinds at high pressure. Physics tells us that water will always find the path of least resistance. It is therefore very important to ensure that the grounds are tamped well and tamped evenly so we achieve a proper and full extraction.  

When done properly no water will escape from the group head, and all the flavour of the coffee is fully extracted.


Getting an even extraction is much more important than getting a forceful one.

espresso coffee tastes bad

To do this you should level the coffee so as grounds are level with the top of the handle (portafilter). I usually do this by curling my finger, and spreading the grains across the top.

The best advice is then to tamp twice. On the first tamp apply light pressure to form the initial puck shape. On the second tamp, apply a bit more pressure, and as you do rotate the tamper a couple of times to distribute and even out the grounds below.

You want to have a smooth even puck, that looks slightly polished. More importantly make sure there are no cracks or gaps.

Some coffee drinkers use an espresso tamping stand and others use a tamping mat to do this. That just keeps things tidier and makes it easier to clean up any spilled grounds.

Water Temperature

This is a smaller problem with espresso machines, as they usually get this fairly accurate. Coffee should be brewed at around 96 degrees and never at boiling point.

At boiling point the coffee grounds may get burned and that leaves a bitter taste. The only way to check what temperature of water is coming out of your machine is to measure it with a thermometer.

More often than not, the temperature will be OK. However when problems do happen it is usually because the water is not hot enough. This tends to happen in older machines. In almost every case there is a problem with the actual boiler, or with the thermostat that controls the boiler.

If it is is regularly producing luke warm coffee then one of those two parts may need replacing. Finding the parts may be a problem and getting them fitted will also not be easy.

Cleaning Your Espresso Machine

Almost all of the bean to cup coffee machines will have some form of self-cleaning and automatic descaling built into them. You still need to do a little bit of work, but generally speaking these expensive machines are very good at cleaning.

With the manual or semi-automatic, the self cleaning will simply vary from model to model. Some will have this and some will not. Likewise the same principle applies to descaling, or the removal of limescale from the pipes, boiler and any heating element.

This decsaling will need to be done more regularly in hard water areas in the United Kingdom.

Conclusion on Bad Tasting Coffee

Freshness is the Key

For coffee lovers, the secret to any great tasting coffee will always be how fresh it is. For the perfect cup of coffee, the beans should be fresh as they can possibly be.

Only every buy as much beans as you plan on using in a couple of weeks. Always store your beans in an airtight container, and out of the light in a cool and dry cupboard. (not in the fridge)

The Perfect Grind

This website is called "The Perfect Grind," for a very good reason. Matching the grind to the type of coffee brewing that your are doing is very important. Get the wrong grind for the particular brewing method you are using, and your coffee will never taste good.

For espresso type machines it should be a fine grind. For filter or pour over, it needs to be a medium/coarse grind.

To do that you do need a quality burr grinder to get it absolutely right. They are the most expensive type of grinder, but we think well worth the money. A blade grinder will do the job of course, but it is a more crude process of grinding.

Buying a Coffee Maker or Coffee Machine

There are many different types of methods for brewing coffee. Most of them, apart from an instant coffee, requires some type of coffee maker, or a coffee machine.

Our advice is that, whichever maker or machine you decide to use, then buy the best one that you can afford, at that time. Avoid cheap makers or machines as they will always be inferior, and the end result is that they will make bad tasting coffee.

Resources Used

Arabica Coffee - Wikipedia

Robusta Coffee - Wikipedia

Instant Coffee - Wikipedia

Enda McLarnon

Enda McLarnon has a Business Management Honour's Degree and applies his professional insight, to analyse and write helpful product reviews with tips and useful advice. I am also a coffee lover and enjoy tasting all of the coffee types the world has to offer.

Enda McLarnon

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