If your espresso tastes sour, the reasons for this can be quickly fixed with the right knowledge and technique. Follow our guide to quickly identify the causes of sour espresso.
You can find a detailed guide on how to prepare great espresso here.
Grind size too coarse - adjust it finer!
If the espresso "shoots" out of the machine, the grind size is too coarse. The grind size should be chosen so that the coffee grounds in the portafilter create enough resistance to hold back the brewing water for the appropriate espresso 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 is worth trying even longer brewing times. Generally, the rule is: the longer we brew the espresso, the less noticeable acidity ends up in the cup.
Note: For machines with pre-infusion or a slow vibration pump, a good brewing time is often between 25 and 30 seconds.
Brew ratio: coffee to liquid
The role that the brew ratio plays in the development of acidity in espresso is often underestimated. Using more coffee to less water always leads to more acidity, especially with short and medium extraction times.
A good coffee-to-water ratio for espresso 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 is also a possible measure.
Note: The more coffee used in proportion to water, the higher the likelihood of "under-extraction 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 starts to taste increasingly sour after a few months or years, it could be because the espresso machine is calcified. In that case, descaling by a specialist is advisable. For some machines, you can also do this yourself.
To reduce acidity, it can also be useful to increase the brewing temperature, i.e., above 93.
Coffee selection
With all changes to settings, it is very important to remember: if the coffee itself already has a lot of noticeable acidity, then we can only reduce it slightly through grind or temperature changes. Therefore, choosing a coffee with less acidity is sensible.
Here are some tips for selecting 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, low-quality Robustas often have "defective" beans, which in turn can taste like unpleasant acidity.
Our tip: try our Fine Robusta Mamy. Low acidity, lots of chocolate, and body in the cup. Plus, you support a social project.
Habit
The influence of habit on the perception of acidity should not be underestimated. Anyone unfamiliar with acidity in coffee experiences it as significantly stronger. Habit is an important factor in sensory perception!
This also means that after the first sip, the acidity is the main thing perceived, which, based on one's own experience, doesn't belong in coffee.
Actually, however, a certain acidity is an important component of good espresso. The English language is more precise here than German, as it distinguishes between "sourness" and "acidity." A certain complex and pleasant acidity is important for good espresso (just as it is for wine) so that the coffee tastes balanced. Sharp and aggressive acidity (under-extraction), however, should be avoided. In this article, we take a closer look at acidity in coffee.
Even if the first sip seems sour and unpleasant at first, it is worth embracing the acidity and tasting whether it is positive or negative acidity. After that, 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 CO2 still present in the coffee, which leads to a carbonated taste in the cup. This acidity is one of the unpleasant tastes in espresso. In addition, the fizzing of CO2 during extraction increases the likelihood of channeling, which promotes unpleasant bitterness and acidity.
Therefore: Espresso is ready to drink approx. 2 to 3 weeks after roasting and has its peak phase up to two months after roasting. That's why we call it a "semi-fresh product."
Bonus tips: Channeling
Even if all the previously discussed tips are followed, you can still occasionally get unexpectedly sour cups. One reason for this could be channeling. Channeling means that the grounds were not distributed evenly in the portafilter. The coffee powder then does not form an even resistance. Instead, there are areas in the portafilter that give way more to the water pressure. The water shoots through these areas at high speed, while it flows too slowly through other areas.
As a result, we have areas of under-extraction on one hand, which leads to more pronounced unpleasant acidity. On the other hand, bitterness is increased by the over-extraction of other areas. Unpleasant acidity and unpleasant bitterness together form a very bad-tasting cup. Something to run away from...
This is also why acidity and bitterness are often experienced together, sometimes mixed up, and then the wrong measures are taken!
The solution here is obvious. Prepare and tamp the coffee in the portafilter evenly and carefully.
Tip: Even though we present a 1:2 brew recipe with 9 to 18 grams in this article, we always recommend brewing a double espresso. The coffee amount of 9 grams is so small that it provokes channeling, especially in large 58mm baskets.
Recommended accessories
Good equipment like baskets and tampers help you brew consistent extractions with less acidity and good results in the cup.
