7 reasons why your espresso tastes too bitter

Written by: Smilla H.



Time to read 6 min

How you can learn from my mistakes and prepare your espresso even better

The portafilter machine of my dreams and the beans from my favorite roastery. I finally have the right equipment for the perfect espresso. The beans go into the grinder, the tamper is used and the first sieve is clamped! The anticipation is great as the coffee flows through the spout. Although I know that the first try never tastes perfect, I naturally have high expectations of my espresso.

The disappointment is all the greater as my taste receptors contract when trying it. Too bitter. The portafilter doesn't forgive us any mistakes, no matter how small. The espresso quickly tastes too sour or too bitter. Many do not even know the difference between these two flavors. You usually perceive the bitter taste of your coffee on the back of your tongue, i.e. in the back of the mouth.

Sometimes it also happens that your coffee suddenly tastes bitter. From the extraction time of the espresso to the degree of grinding to your accessories and the beans used - the unpleasant taste experience can have various reasons. To save you the frustration and desperation in espresso preparation, here are 7 tips on what can go wrong and how your espresso next-level becomes delicious!

Mistake #1: Your grind is too fine

The correct degree of grinding is the be-all and end-all in every type of preparation. The portafilter machine does not forgive any inaccuracies here. If the grind is set too fine, your espresso will be over-extracted and therefore too bitter.

From my experience, it is worth investing time here and setting the coffee grinder carefully! It's a bit of a hassle at first, but once you've found the right degree of grind for your favorite beans, you only have to make a few adjustments. With some grinder models, you can even save grinding settings and get back to a specific degree of grinding and a specific grinding speed in no time at all. We're in the very high-priced segment here, but what don't you do for a good espresso, right? The next faux pas is directly linked to the right degree of grinding...

Ground coffee comes from the mill into the sieve

Mistake number 2: Your espresso runs too slowly

The extraction time of the coffee is almost always linked to the degree of grinding of the coffee bean. Fine coffee powder increases the resistance in your portafilter, the brewing pressure and your brewing time. If you overdo it here, your espresso will over-extract and become too bitter.

Another reason: too much ground coffee in the portafilter. In either case, it becomes more difficult for the water to force its way through the coffee powder, resulting in a very slow extraction and making the espresso too bitter. Incidentally, the ideal target time for the portafilter machine is between 25 and 40 seconds. How long your espresso should take depends primarily on your taste and the roast.

Espresso runs from the portafilter machine into the cup

Mistake #3: Your beans are roasted too dark

Now let's get down to business! You have no direct influence on the roasting of your coffee beans. But: Keep your eyes open when buying beans! It took me a while to try my way through the roasting jungle and find my personal favorite beans. You're lucky, that's what we're here for!

Specialty coffee experts would advise against the long-established, dark roasts. When coffee beans are roasted too dark and too long, they lose many of their unique and delicate flavors. What remains are the dominant, bitter aromas. This means very dark roasts tend to have a bitter end result.

If you're looking to get into the specialty coffee business, then it's worth trying lighter roasts. Of course, "classic" roasts are not only bad, in the best case you can expect great chocolate and nutty taste experiences! Of course, you should make sure that your beans always stay fresh. That means storing it tightly sealed and in a dry place and always grinding it fresh and just before preparing the espresso.

Roaster examines beans from roast drum

Mistake #4: Poor preparation

An essential step in espresso preparation is the preparation! The distribution and compression of the ground coffee is also called "puck prep". Everything that happens prior to clamping your screen is super important to the end result. How the water finds its way through the sieve affects the brewing time and thus the dissolved coffee aromas. So it's about creating a nice coffee bed in the sieve so that the water can flow through evenly. Here we go!

The distribution of the ground coffee

In order to avoid the so-called "channeling", pay attention to an even distribution when filling in the coffee powder. If you want to be on the safe side here, use a leveler. This distributes the powder evenly in the portafilter and thus prevents channeling.

The tamping of the ground coffee

The pressure that we then apply to the tamper to press the ground coffee down also affects the brewing pressure and the brewing time. If you press too timidly, larger air pockets may remain in the coffee bed in some places. Here, too, unpleasant channeling occurs.

Portafilter with tamper

Mistake number 5: The ratio of coffee and water

Here we tie in again with the thorough preparation before the actual espresso preparation. As you can see, there are a few sources of error here. We look at the amount of coffee in the strainer in relation to the water that runs through the strainer. We get to the bottom of this with the good old coffee scale.

A good starting point is a 1:2 ratio. That means 19 grams of ground coffee in the portafilter, 38 grams of espresso in the cup. If your end result tastes bitter and a bit flat, let a little less water run through. However, the running time should not be less than 25 seconds.

Mistake number 6: The wrong screen

Especially as a beginner, it is easier to work with a double cover, i.e. a sieve with two outlets. Small screens often have a different shape and converge towards the bottom. As a result, the susceptibility to error in the "puck prep" with a simple reference is much higher.

So if you want to make it easier for yourself, use a large sieve. If a simple espresso is enough for you, your roommate or partner might also be happy about a delicious coffee! Another little tip for the summertime and to avoid wasting a precious espresso: leftover espressos are great for an iced coffee!

Sieve tamped with ground coffee

Mistake number 7: Brewing temperature too high

The brewing temperature for espresso should be between around 90° and 94°. Especially with cheaper models, it can happen that the remaining water in the machine heats up a little too much. If you now draw your espresso, it will probably be a bit bitter. A quick rinse out of the machine helps here. This means simply letting some water run through without a clamped portafilter. For machines with temperature adjustment (PID) you can of course simply adjust it down a bit.

Making the perfect espresso - bonus tips

water quality

The water used is an important part of your espresso and can affect the taste. If your water is too soft or too hard, your espresso may end up being a bit too bitter or too acidic. You can remedy this with Third Wave Water, for example. With the addition, you create the perfect conditions for a perfect shot - every time.

coffee bean quality

It can also happen that you got bad coffee beans, even with expensive varieties. Just try a second cup and you'll know if it was the beans. And now you know where to find good beans!

Practice makes perfect!

Everything good takes time and practice, don't give up! After some time, you will better understand which variables change the taste of your espresso. I hope I was able to help you with this article and you were able to unmask the source of the error. Happy Brewing!

Beans in roasting drum

Making the perfect espresso - bonus tips

Why does my espresso taste too bitter?

The bitterness of your espresso can have different causes. The most common reasons are too fine a grind, too long an extraction time, too dark roasted beans and poor preparation of the coffee grounds.

How can I set the right degree of grinding?

The right degree of grinding is crucial for a good espresso. Invest time in fine-tuning your coffee grinder until you have found the optimal degree of grinding for your favorite beans. Some grinder models even allow grinding settings to be saved.

Why is my espresso running too slowly?

Too fine a grind and too much ground coffee in the portafilter can cause the espresso to flow through too slowly, leading to over-extraction, resulting in bitterness. The ideal extraction time is usually between 25 and 40 seconds.

How do the beans affect my espresso quality?

The roasting of the beans has a major impact on the taste of your espresso. Beans that are roasted too dark tend to taste bitter.