6 Coffee Machine Mistakes You’re Probably Making

The best coffee machines are designed to make aromatic espresso with a rich crema – but they can’t work miracles. Even small mistakes can affect the taste of your coffee, regardless of the quality of your machine.

For this reason, we’ve put together a list of the most common mistakes when brewing espresso with a bean-to-cup coffee machine. If your coffee is bitter, flat or just a bit disappointing, you’re probably making one of these mistakes.

1. Your Water is Ruining Your Coffee

Buying an expensive coffee machine and filling it with tap water is the #1 mistake you can make. While all water might look the same, the chemical and mineral balance has a big effect on taste.

It’s not as simple as just avoiding hard water though. Yes, filtered water is always going to taste better than overly hard water. But the presence of certain amounts of hard minerals, such as calcium, can actually enhance flavour.

To learn about the perfect water composition for coffee, check out my complete guide here.

2. Your Coffee Has Gone Stale

One of the main advantages of a bean-to-cup machine is that you get freshly ground coffee for each brew. Flavoursome oils trapped within coffee beans start to evaporate almost immediately after grinding, so whole-bean coffee tastes a lot fresher. In fact, once you’ve tasted the difference between fresh and pre-ground coffee, it’s hard to go back!

This doesn’t mean whole beans stay fresh forever though. And as beans starts to go stale, they lose their freshness, flavour and consistency.

For this reason, it’s important to check the roasting date when you buy a batch of coffee. Ideally, you should use your coffee within a month of buying for maximum flavour. I recommend buying smaller batches more frequently and storing in a dark location within an airtight container.

There’s also the option of using a coffee subscription service. These deliver whole-bean coffee to your door on a regular basis, so you’ll always have fresh beans available.

3. You’re Not Maintaining Your Bean-To-Cup Coffee Machine

When you buy an expensive bean-to-cup coffee machine, you’re probably thinking about the aromatic coffee you’ll be drinking each morning – not about cleaning it.

All coffee machines require some maintenance though. It’s important to prevent build-up of leftover coffee or limescale, as this can affect the taste of your coffee. Failure to clean the machine can also allow bacteria and other nasty contaminants to accumulate.

The best way to maintain your machine is by reading the manufacturer’s instructions carefully. Every manufacturer provides instructions on how and when to clean each part of the machine, including when to use the descaling program. You’ll also need to manually clean the brew group to prevent coffee build-up.

It’s a good idea to create a regular schedule for cleaning. This ensures your machine is always ready to make a great cup of coffee. I use an app called Todoist to set recurring reminders, but you could also just write it in your diary.

For more information about cleaning a bean-to-cup coffee machine, here’s our in-depth guide. And if you haven’t chosen your machine yet, here’s our list of the top models: https://beantocupcoffee.co.uk

4. Your Beans are Poor Quality

It's essential to choose the right beans

You can spend £1000+ on the best bean-to-cup coffee machine – but if the beans are poor quality, you’ll never brew the coffee you deserve.

The best coffee beans depend on your personal taste. Local roasters are often a great place to start, as you get the freshest beans from people who are truly passionate about roasting. In contrast, supermarket coffee should nearly always be avoided, as the beans are probably low quality and stale.

Here are some more tips for choosing the best beans:

  • Arabica beans are always the higher quality option compared to Robusta. These beans are grown on taller mountains and higher elevations, so they develop slower to contain more flavour. The only advantage to Robusta – aside from being easier to grow – is the higher caffeine content.
  • Choose a growing location that matches your acidity tastes. African beans tend to have higher levels of acidity, while South American are often more “nutty.” Also, acidity is not the same thing as bitterness. A bitter coffee has usually been too finely ground.
  • Blended beans aren’t always a bad choice. If the blend has been chosen carefully by a professional, it can provide a unique flavour with a balanced acidity and body. Avoid companies that blend expensive beans with lower quality ones just to save money though.

Unfortunately, you tend to get what you pay for when it comes to buying coffee beans. So, be prepared to spend a bit extra on the highest quality beans.

5. You Don’t Experiment With Your Machine’s Settings

Most espresso machines have options for adjusting the coffee output. These might include water temperature, grind coarseness and coffee strength.

As you might expect, these settings can make a big difference to the ultimate taste of your coffee. The problem is that they can also be overwhelming, as even subtle changes can have surprising effects – especially when you’re first learning how to use the machine.

Unless you have a fully developed coffee palate, however, experimentation is key. Try adjusting the grind coarseness to see how it affects bitterness, for example. You’ll learn much more about how to brew a great coffee that’s customised to your tastes.

The ideal settings may also vary depending on the type of bean you use. A highly acidic bean, for example, probably needs a coarser grind to prevent bitterness.

6. You’re Drinking from Plastic Cups

Coffee always tastes better in a ceramic or glass cup. If you’re travelling, a stainless steel flask is a good alternative, as your coffee stays warmer for longer.

You should never drink coffee from a plastic cup or flask though. Aside from making your coffee taste worst, hot fluids may allow BPA to leak into your drinks, which could be dangerous.


The best coffee machines make brewing barista-standard coffee much more accessible. They take care of grinding, tamping and brewing for you, so you just need to learn how to adjust the settings to your tastes.

There are still plenty of mistakes that can affect your espresso though. Even relatively minor issues, such as using stale beans or forgetting to clean the brew unit, can have a major impact on your coffee.

You shouldn’t give up or get frustrated though. Every mistake is a learning opportunity. And, before you know it, you’ll be making perfect espresso every time.

Have a question or comment? Let us know!

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