There was a time when I was utterly frustrated with my home espresso-making attempts. I remember vividly one morning when I tried pulling what felt like my hundredth shot, only to be met with that familiar taste of disappointment: a thin, sour shot that lacked all the magic I expected. I had been dreaming of a rich, creamy espresso to kickstart my day, but instead, I ended up with something I could barely stomach. It was then that I decided enough was enough—I had to figure out what was going wrong. After weeks of experimenting, tweaking my espresso machine settings, and making mistake after mistake, I finally got it right. Now, I want to help you avoid those sour shots and enjoy espresso the way it's meant to be. Explore the features and performance of this machine in our Philips 5500 LatteGo review
Let me guide you through everything I've learned about fixing under-extracted espresso. Dive into the details of the Philips 5400 LatteGo review
What is Under-Extraction?
Before diving into the solutions, it’s essential to understand what under-extraction is and why it happens. Under-extraction occurs when the water passes through the coffee grounds too quickly, not allowing enough time to draw out the soluble flavors of the coffee. This results in espresso that tastes weak, sour, and acidic—flavors we definitely don’t want dominating our cup. On the opposite end, over-extraction leads to a bitter, overly intense shot. To brew great espresso, the key is to achieve the right balance. Compare these two models in our Philips LatteGo 5400 vs 4300 review
Signs that your espresso is under-extracted include:
- Sour or Sharp Acidity: The kind of harsh sourness that isn't refreshing but overpowering.
- Thin Body: A watery texture that lacks the richness or thick creaminess of well-extracted espresso.
- Pale Crema: Properly extracted espresso has a thick, golden-brown crema, whereas under-extracted shots yield a pale, thin crema.

Now that we understand the symptoms, let’s get into how we can fix this by adjusting a few key variables. Discover the differences between these machines in our Philips 3200 vs 4300 vs 5400 review
1. Adjust the Grind Size
The grind size is one of the most crucial factors in espresso extraction. For espresso, you need a very fine grind, almost like powdered sugar. If the coffee grounds are too coarse, the water flows through them too quickly, leading to under-extraction. Learn how these two models compare in our Philips 3200 vs 4300 review
When I first started making espresso, I underestimated how even a tiny adjustment in grind size could make a big difference. If your espresso is tasting sour and weak, the first adjustment you should make is grinding your coffee finer. A finer grind increases the surface area of the coffee, allowing the water to extract more flavors. However, make sure you don’t grind too fine, as that can lead to over-extraction and a bitter taste. Uncover the key distinctions in our Philips 3200 vs 5400 review
Tip: Make small, incremental changes to the grind size and test each shot until you find the sweet spot. This approach can help you dial in the perfect grind for your espresso machine and beans.
2. Adjust Your Brew Ratio
Another important factor in fixing under-extracted espresso is the brew ratio, which refers to the amount of coffee grounds versus the amount of water used. Typically, an espresso brew ratio is 1:2, meaning if you start with 18 grams of coffee, you should end up with about 36 grams of espresso in your cup. If your espresso tastes under-extracted, you may be using too little coffee or too much water.
Start by adjusting your dose (the amount of coffee grounds). Try increasing the dose slightly to give the water more grounds to extract flavor from, or reduce the yield (the amount of espresso produced) to create a more concentrated shot.
When I faced problems with under-extraction, simply changing my brew ratio made a huge difference. Using a small kitchen scale to weigh both the coffee and the resulting shot gave me much better control and consistency in my results.
3. Check Your Water Temperature
Water temperature plays a huge role in proper espresso extraction. If the water is too cool, it won’t extract the coffee’s flavors efficiently, resulting in an under-extracted, sour-tasting shot. The ideal temperature for brewing espresso is between 195°F and 205°F (90°C to 96°C).
I discovered my machine was brewing too cool after some troubleshooting, and that explained my consistently sour shots. If your machine doesn't let you adjust the water temperature, make sure it is properly warmed up before brewing. Let the machine heat up for a good 15-20 minutes before making your espresso.
If your espresso machine has adjustable temperature settings, try raising the temperature slightly, but remember—a temperature too high will over-extract and produce bitter flavors. Gradual adjustments are key.
4. Refine Your Tamping Pressure
Tamping the coffee grounds in the portafilter is another crucial step. If you tamp too lightly, the water will rush through the grounds, leading to under-extraction. If you tamp too hard, it could lead to the opposite problem—over-extraction.
In the beginning, I didn't realize how important consistent tamping was. The goal is to apply about 30 pounds of pressure, creating a firm, even surface for water to pass through uniformly. A simple trick is to practice with a bathroom scale until you get a good feel for what 30 pounds of pressure feels like. Consistency here is the key to avoiding uneven extraction.
5. Adjust Shot Time
Shot time is another important factor in achieving a well-balanced espresso. The ideal shot time typically falls between 25 and 30 seconds. If your shot is pulling too quickly (e.g., under 20 seconds), there’s a strong likelihood that your espresso is under-extracted.
To increase shot time, try grinding your coffee finer, tamping more firmly, or increasing the coffee dose. All of these adjustments will help the water take more time to work through the coffee grounds, leading to a more complete extraction.
When I first started, I didn’t pay much attention to shot time. But after I started timing my shots, I realized how much impact a few extra seconds could have on the flavor. These days, I always make sure my shots are within the 25-30 second range to ensure consistent quality.
6. Fresh Coffee is Key
One of the most overlooked aspects of espresso extraction is the freshness of the beans. Coffee beans start to lose their flavors and oils shortly after roasting, and if your beans are stale, even the best technique won’t save your shot from being under-extracted and flat.
I used to use beans that had been sitting around for weeks, without realizing how much it affected the taste of my espresso. Now, I make sure to use beans that were roasted within the past two weeks. Freshly roasted beans have more aromatic oils and soluble compounds, which significantly improve the extraction and the quality of the shot.
Conclusion: Achieving the Perfect Shot
Fixing under-extracted espresso is all about fine-tuning different variables—from grind size, brew ratio, and water temperature, to tamp pressure and shot time. While the process may seem overwhelming at first, each adjustment brings you closer to that perfect, rich, and well-balanced shot. If you find yourself with a sour or weak espresso, don’t see it as a failure—use it as an opportunity to refine your skills.
In my own journey, even small tweaks made a huge difference, and over time, I grew more confident in my espresso-making abilities. With practice and patience, you'll be pulling shots that rival your favorite café's espresso. So hang in there, enjoy the process, and happy brewing!

Frequently Asked Questions
Q: What causes under-extracted espresso?
A: Under-extraction occurs when the water passes too quickly through the coffee grounds, which prevents enough of the flavors from being extracted. This can be due to coarse grind size, too little coffee, low water temperature, or insufficient tamping pressure.
Q: How do I know if my espresso is under-extracted?
A: Signs of under-extracted espresso include a sour, sharp taste, a thin body, and pale, thin crema. It will often lack the depth and complexity of a properly brewed espresso.
Q: How can I fix under-extracted espresso?
A: You can fix under-extraction by adjusting the grind size (making it finer), increasing the coffee dose, ensuring the water temperature is between 195°F and 205°F, tamping with about 30 pounds of pressure, and aiming for a shot time of 25-30 seconds.
Q: Does the freshness of coffee beans affect extraction?
A: Yes, fresh coffee beans make a big difference in the quality of your espresso. Beans that are older than a few weeks lose their aromatic oils and solubles, leading to poor extraction and dull flavors.
Q: How does grind size affect espresso extraction?
A: The grind size directly affects how fast the water flows through the coffee grounds. A grind that is too coarse will lead to water passing through too quickly, resulting in under-extraction. A finer grind increases the surface area, allowing for better extraction.