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.
You can find a detailed guide on how to make good espresso here.
Grind too coarse - adjust to finer!
If the espresso shoots out of the espresso machine, then the grind is too coarse. The grind should be chosen so that the coffee powder in the portafilter provides sufficient resistance to hold back the brewing water in 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's also worth trying even longer brewing times. As a general rule: the longer we brew the espresso, the less perceivable acidity lands in the cup.
Note: With machines that have pre-infusion or a slow vibration pump, a good brewing time is often between 25 and 30 seconds.
Drink ratio: coffee to liquid
The role that the drink ratio plays in the development of acidity in espresso is often underestimated. More coffee used relative to less water always leads to more acidity, especially with short to medium extraction times.
A good ratio of coffee to water in the espresso range is 1:2 or 1:2.5.
Applied to a recipe, this means:
- 1:2 ratio: 9 grams of coffee powder becomes 18 grams of espresso
- 1:2.5 ratio: 9 grams of coffee powder becomes 22.5 grams of espresso
In some cases, with coffees that have a lot of acidity, a brew ratio of 1:3 is also an option.
Note: The more coffee is used in relation to water, the more likely we have "under-extraction acidity." This acidity is always unpleasant!
Temperature - too cold is sour!
Temperature during brewing 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 may be because the espresso machine is scaled up. In that case, descaling by a specialist is advisable. With some machines, you can also do it yourself.
To reduce acidity, it can also be useful to increase the brewing temperature, so above the 93.
Coffee selection
When making all adjustments, it is very important: if the coffee itself already brings a lot of perceivable acidity, we can only reduce the acidity slightly through changes in grind or temperature. That's why choosing a coffee with less acidity is worthwhile.
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, so acidity is not the focus. However, be careful, especially inferior Robustas often have "defective" beans, which in turn can taste like unpleasant acidity.
Our tip: try our Fine Robusta Mamy. Little acidity, lots of chocolate and body in the cup. And in addition, you 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 experience it as much stronger. Habit is an important factor in sensory perception!
This also means that after the first sip, acidity is especially perceived, which, according to one's experience, doesn't belong in coffee.
Actually, a certain amount of acidity is an important component of good espresso. English is more precise here than German, 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 in itself. Sharp and aggressive acidity (under-extraction) should be avoided. In this article we look more closely at acidity in coffee.
It's worth trying, even if the first sip initially seems sour and unpleasant, to embrace the acidity and taste whether it's a positive or negative acidity. Afterwards, measures can still be taken to counteract the acidity in the coffee...
Fresh coffee
Too fresh coffee is also sour! This is due to the CO2 still present in the coffee, which in the cup leads to a taste of carbonation. This acidity counts as one of the unpleasant flavors 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 until about two months after roasting. That's why we also speak of a "semi-fresh product."
Bonus tips: Channeling
Even if all the tips discussed earlier are heeded, it can still happen that occasionally unpleasantly sour cups occur. One reason for this could be channeling. Channeling means that the grounds were not evenly distributed in the portafilter. The coffee powder then also doesn't form uniform resistance. Instead, there are coffee areas in the portafilter that give way more to the pressure of the water. Through these, the water shoots through at high speed, while it flows too slowly through other areas.
This results in areas with under-extraction on the one hand, which leads to a more pronounced unpleasant acidity. On the other hand, bitterness from the over-extraction of other areas is increased. Unpleasant acidity and unpleasant bitterness then together form a very poorly tasting cup. Enough to run away from...
This is also why acidity and bitterness are often experienced together, sometimes confused, and then inappropriate measures are taken!
Yet the measure here is obvious. Prepare and tamp the coffee in the portafilter evenly and carefully.
Tip: Even though we present a brewing recipe of 1:2 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 especially provokes channeling with large 58mm baskets.
Recommended equipment
Good equipment such as baskets and tampers support you in brewing uniform extractions with less acidity and good results in the cup.
