If your espresso tastes sour, the reasons can be quickly remedied with the right knowledge and technique. Follow our guide to quickly find the causes of sour espresso.
A detailed guide on how to prepare good espresso can be found here.
Grind too coarse - make it finer!
If the espresso "gushes" out of the espresso machine, then the grind is too coarse. The grind should be chosen so that the coffee grounds in the portafilter create sufficient resistance to hold back the brewing water for the appropriate espresso extraction time. In almost all cases, a good brewing time is between 22 and 28 seconds.
Only a few coffees require longer brewing times. If the coffee still tastes sour, it's worth trying even longer brewing times. Generally, the longer we brew the espresso, the less noticeable acidity ends up in the cup.
Note: For machines with pre-infusion or a slow vibratory pump, a good brewing time is often between 25 and 30 seconds.
Brew Ratio: Coffee to Liquid
The role of the brew ratio in the development of acidity in espresso is often underestimated. More coffee used to less water always leads to more acidity, especially with short and medium extraction times.
A good coffee-to-water ratio in the espresso range is 1:2 or 1:2.5.
Applied to a recipe, this means:
- 1:2 ratio: 9 grams of coffee grounds become 18 grams of espresso
- 1:2.5 ratio: 9 grams of coffee grounds become 22.5 grams of espresso
In some cases, for coffees with a lot of acidity, a 1:3 brew can also be a measure.
Note: The more coffee used in relation to water, the higher the probability of "underextraction acidity." This acidity is always unpleasant!
Temperature - too cold is sour!
The brewing temperature also plays a major role in extraction! We generally recommend a brewing temperature of around 93 degrees Celsius. Lower temperatures, in particular, strongly emphasize the acidity of the espresso.
If your espresso becomes increasingly sour after a few months or years, it could be due to limescale build-up in the espresso machine. In this case, descaling by a specialist company is advisable. You can also do this yourself with some machines.
To reduce acidity, it can also be useful to increase the brewing temperature, i.e., above 93 degrees.
Coffee Selection
With all changes in settings, it is very important: if the coffee itself already brings a lot of perceptible acidity, then we can only slightly reduce the acidity by changing the grind or temperature. Therefore, selecting a coffee with less acidity makes sense.
There are some tips for choosing coffee with less acidity:
- Darker roasts show less acidity but are often more bitter.
- Arabica leads to more acidity in the cup. Robusta is earthier, stronger, and more bitter, which is why acidity is not the focus. But beware, especially low-quality Robustas often have "defective" beans, which can then taste unpleasantly sour.
Our tip: try our Fine Robusta Mamy. Low acidity, lots of chocolate and body in the cup. And you also support a social project.
Habit
The influence of habit on the perception of acidity should not be underestimated. Those who are not familiar with acidity in coffee perceive it as significantly stronger. Habit is an important factor in sensory perception!
This also leads to the perception of acidity primarily in the first sip, which, according to one's own experience, does not belong in coffee.
However, a certain acidity is an important component of good espresso. The English language is more precise than German in this regard, as it distinguishes between "sourness" and "acidity." A certain complex and pleasant acidity is important for good espresso (as for wine) so that the coffee tastes balanced. Sharp and aggressive acidity (underextraction) should be avoided. In this article, we delve deeper into acidity in coffee.
It's worth it, even if the first sip initially seems sour and unpleasant, to embrace acidity and discern whether it is positive or negative. Afterwards, measures can still be taken to counteract the acidity in the coffee...
Fresh Coffee
Coffee that is too fresh is also sour! This is due to the remaining CO2 in the coffee, which leads to a carbonic acid taste in the cup. This acidity is one of the unpleasantly tasting ones in espresso. In addition, the bubbling of CO2 during extraction increases the likelihood of channeling, which promotes unpleasant bitterness and acidity.
Therefore: espresso is ready to drink about 2 to 3 weeks after roasting and is at its best up to two months after roasting. That's why we also refer to it as a "semi-fresh product."
Bonus Tips: Channeling
Even if all the previously discussed tips are followed, it can still occasionally lead to unpleasantly sour cups out of the blue. One reason for this could be channeling. Channeling means that the grounds were not evenly distributed in the portafilter. The coffee powder then also does not form a uniform resistance. Instead, there are coffee areas in the portafilter that yield more to the pressure of the water. The water then shoots through these areas at high speed, while it flows too slowly through other areas.
As a result, we have areas of underextraction, which leads to a more pronounced unpleasant acidity. On the other hand, the bitterness is increased by the overextraction of other areas. Unpleasant acidity and unpleasant bitterness then together form a very bad-tasting cup. Makes you want to run away...
This is also why acidity and bitterness are often experienced together, sometimes mixed up, and then inappropriate measures are taken!
However, the measure here is obvious. Prepare and tamp the coffee in the portafilter evenly and carefully.
Tip: Even though in this article we present a brewing recipe of 1:2 with 9 to 18 grams, we always recommend brewing a double espresso. The coffee quantity of 9 grams is so small that it provokes channeling, especially with large 58mm baskets.
Recommended Accessories
Good equipment like baskets and tampers help you to brew even extractions with less acidity and good results in the cup.
