Frequently Asked Questions
Why does my espresso taste bitter?
The cause is usually over-extraction, water that is too hot, or old beans.
Why doesn't my espresso have crema?
The most common reasons are stale beans, incorrect grind size, or unsuitable extraction.
Why does espresso taste sour?
Often the coffee is underextracted or the beans are very lightly roasted.
Which beans are suitable for low acidity?
Classic Italian espresso roasts with a balanced profile and fresh roasting.
Which grind size is right?
The right grind size is one where your espresso tastes balanced and reaches the desired volume in the correct time.
As a starting point:
- Espresso extracts too fast → grind finer
- Espresso extracts too slow → grind coarser
- Sour taste → usually grind finer
- Bitter taste → usually grind coarser
With a classic setting, approximately 36–40 g of espresso should be produced from 18–20 g of coffee grounds in about 25–30 seconds. In our FORMA Guide, you will find all the information on how to prepare our espresso.
How many grams of coffee for an espresso?
This depends on the portafilter:
Beverage : Coffee Quantity
Single Espresso 7–10 g
Double Espresso 16–20 g
Triple Shot 20–24 g
Most modern espresso machines today use a double basket. Therefore, 18 g is a good starting point.
How long should an espresso shot pull?
The often-cited 25-30 seconds is a guideline, not a rule.
More important than time are the taste and the ratio of coffee to espresso.
Basic rule:
- Under 20 seconds → often underextracted, sour, thin
- 25–30 seconds → usually a good starting point
- Over 35 seconds → often overextracted, bitter
If the espresso tastes excellent, then 22 or 35 seconds are perfectly fine too.
When do I stop receiving benefits?
Orient yourself by the so-called brew ratio.
For a classic espresso:
- 18 g ground coffee
- 36 g espresso in the cup
This corresponds to a ratio of 1:2.
Examples:
Coffee : Espresso
18 g : 36 g
19 g : 38 g
20 g : 40 g
Therefore, a scale is much more helpful than volume in milliliters, as crema strongly affects the volume.
What exactly is a "proper" espresso?
An espresso is a concentrated coffee, extracted under pressure through finely ground coffee powder.
Typical characteristics:
- Intense flavor
- Full body
- Pleasant sweetness
- Balanced bitterness
- Fine acidity
- Hazelnut-colored crema
A good espresso tastes neither solely bitter nor solely sour, but balanced and clear - just like our EXTRA BAR Espresso.
Why don't I have crema?
The most common causes are:
The beans are too old
Freshly roasted beans contain CO₂, which is responsible for the crema.
Ideal:
- 1–8 weeks after roasting
Grind size too coarse
The water flows too quickly through the coffee bed.
Too little coffee in the portafilter
The resistance is too low.
Brewing pressure too low
The machine does not reach sufficient pressure.
Unsuitable beans
A certain proportion of Robusta often produces more and more stable crema than pure Arabica blends.
Which beans are best for espresso?
Beans with a medium to dark roast are particularly suitable for espresso.
100% Arabica
Characteristics:
- More fruitiness
- More acidity
- More complex aromas
- Finer crema
Suitable for:
- Pure espresso
- Specialty coffee
Arabica-Robusta Blends
Characteristics:
- More body
- More crema
- Less acidity
- Stronger taste
Suitable for:
- Italian espresso
- Cappuccino
- Latte Macchiato
Dark Italian Roasts
Typical aromas:
- Chocolate
- Nuts
- Cocoa
- Caramel
They are considered particularly beginner-friendly and harmonize excellently with milk-based drinks.
Why does my espresso taste sour despite good beans?
If your espresso tastes sour, it's usually not due to the beans but to the extraction. Even high-quality beans can taste unpleasantly sour if the flavors are not fully extracted.
1. The grind is too coarse
The most common cause of sour espresso is a grind that is too coarse. The water flows too quickly through the coffee grounds, primarily extracting the fruity and acidic components, while sweetness and body are lacking in the cup.
Solution: Adjust the grind slightly finer and test again.
2. The extraction time is too short
If your espresso runs through in less than 20–25 seconds, it is often referred to as under-extraction. The espresso then tastes thin, unbalanced, and acidic.
Solution: The target time is approximately 25–30 seconds for a classic espresso.
3. The coffee-to-espresso ratio is incorrect
If, for example, 50 g of espresso are obtained from 18 g of coffee grounds, the extraction may run too far. Conversely, a very short extraction can also lead to a sour result.
Solution: Start with a 1:2 ratio. From 18 g of coffee grounds, approximately 36 g of espresso should be produced.
4. The brewing temperature is too low
If the water is not hot enough, many sweet and balanced aromas are not sufficiently extracted. The result can be a sour taste.
Solution: The brewing temperature should usually be between 92 and 96 °C.
5. The beans are very lightly roasted
Not all acidity is a defect. Modern, lightly roasted espresso beans often deliberately have fruity notes reminiscent of berries, citrus fruits, or stone fruit.
Solution: Those who prefer a classic Italian espresso tend to choose medium to dark roasted beans with chocolatey and nutty aromas.
6. The beans are too fresh
Immediately after roasting, coffee beans still contain a lot of CO₂. This can cause the espresso to extract unevenly and taste unbalanced.
Solution: Most espresso beans develop their full aroma after a resting period of about 7 to 14 days after roasting.
7. The bean blend does not suit your taste
Many modern espresso blends rely on 100% Arabica or very light roasts. These can deliberately produce more fruit acidity and vibrant flavors. However, those who prefer the classic Italian espresso with a lot of body, crema, and low acidity often find such coffees too sour.
Solution: Try a balanced espresso blend with a Robusta content. The beans from caffè di FORMA consist of a carefully balanced 50/50 blend of Arabica and Robusta. The result is a full-bodied espresso with dense crema, chocolatey notes, and significantly less acidity. Many coffee lovers who perceive a sour taste with other beans therefore prefer the balanced and Italian-inspired roast from caffè di FORMA.
The most important rule of thumb
If you only want to remember three values:
- 18 g coffee
- 36 g espresso in the cup
-
25–30 seconds extraction time
From there, you can adjust the grind and recipe to your taste.