Espresso Under-Extraction? What To Do To Fix It

Learn how espresso under-extraction affects flavor! Get expert tips to perfect your brew. Read now!

What is Espresso Under-Extraction? 

Under-extraction in espressos occurs when water passes through coffee grounds too quickly. This process fails to extract essential oils and flavors, leading to a sour and weak taste. The issue can often be corrected by adjusting grind size or brewing time, improving the overall quality of the espresso.

Barista using coffee maker

The Causes of Under-Extraction

Under-extraction in the context of making coffee, particularly espresso, is a topic that involves several key factors. This phenomenon occurs when the water flows through the coffee grounds too quickly, not allowing enough time to extract all the desired flavors and aromas. 

The result can be a sour and weak coffee that lacks complexity. Here are some of the primary causes of under-extraction:

Grind Size

When the coffee is ground too coarsely, water can flow through the grounds too quickly, leading to under-extraction. Finding the right balance in grind size is crucial for optimal espresso extraction.

Brewing Time

If the espresso is brewed too short, there might need to be more time to extract the flavors thoroughly. The recommended brewing time for espresso is typically between 25 and 30 seconds.

Water Temperature

Utilizing too cool water can slow the extraction process. The ideal temperature for extracting espresso is around 195 to 205 degrees Fahrenheit (90 to 96 degrees Celsius).

Tamping Pressure

Inconsistent or too-light tamping can cause uneven water flow, leading to pockets of under-extracted coffee. Applying even and proper pressure when tamping ensures uniform extraction.


Using too little coffee in relation to water can also cause under-extraction. Ensuring the correct ratio of coffee to water is essential for achieving the right balance of flavor and strength.

Machine Calibration

Regular maintenance and calibration of the espresso machine ensure that all parts work efficiently. Any malfunction can lead to irregularities in pressure and temperature, contributing to under-extraction.

Bean Quality

Fresh, high-quality beans are essential for complete flavor extraction. Stale or low-quality beans can produce lackluster flavor and contribute to under-extraction.

In conclusion, understanding and controlling the variables that affect espresso extraction is critical to preventing under-extraction. It requires combining the right equipment, techniques, and high-quality ingredients to create the perfect cup of espresso. 

By paying attention to details like grind size, brewing time, water temperature, and tamping pressure, one can master the art of espresso-making and avoid the common pitfalls of under-extraction.

Over-Extraction vs. Under-Extraction

Over-extraction and under-extraction are two terms that coffee enthusiasts and baristas often discuss, especially in the context of espresso making. Both significantly impact the taste and quality of the espresso, and understanding their differences is crucial for anyone striving to perfect their espresso brewing skills.

Over Extraction


Over-extraction occurs when the brewing process takes too long or the coffee grounds are too fine. This leads to the extraction of undesirable flavors, resulting in a bitter and astringent taste.


  • Grind Size: Too fine a grind can slow down the water flow, leading to over-extraction.
  • Brewing Time: Brewing the espresso for too long allows the extraction of unwanted compounds.
  • Water Temperature: Excessively hot water can expedite extraction, contributing to over-extraction.
  • Impact on Flavor: The over-extracted espresso has a harsh and unpleasant taste, lacking subtle notes and complexity.

Under Extraction


Espresso under-extraction happens when the water flows through the coffee grounds too quickly or the grounds are too coarse. This prevents the complete extraction of flavors, leading to a sour and weak taste.


  • Grind Size: A coarse grind allows water to pass through quickly, causing under-extracted espresso.
  • Brewing Time: A short brewing time doesn’t allow full flavor extraction.
  • Water Temperature: Cool water can inhibit extraction, contributing to espresso under-extraction.
  • Impact on Flavor: An under-extracted espresso is often characterized by a lack of depth, complexity and can have a sour taste.


  • Flavor Profile: Over-extraction leads to bitterness, while under-extracted espresso results in sourness.
  • Texture and Appearance: Over-extraction can create a thick and muddy appearance, whereas under-extraction often produces a thin and pale shot.
  • Solution: Both problems can often be resolved by adjusting grind size, brewing time, and water temperature.

In conclusion, both over-extraction and espresso under-extraction play crucial roles in determining the quality of espresso. By understanding the differences and how to control these aspects, baristas and coffee lovers can fine-tune their techniques to create the perfect cup of espresso, reflecting both their preferences and the unique characteristics of the coffee beans.

Coffee machine extracting coffee

How to Fix Underextracted Espresso

Fixing under-extracted espresso is a common challenge many baristas and coffee enthusiasts face. Underextracted espresso can taste sour and weak, lacking the rich and complex flavors that characterize a well-brewed cup. 

Understanding the causes of espresso under-extraction and implementing specific techniques can help rectify this issue. Here’s a step-by-step guide to addressing under-extracted espresso shots:

Adjust Grind Size

Problem: Coarse grind size allows water to flow through the coffee grounds too quickly.

Solution: Grind the coffee beans to a finer consistency to slow down the extraction process and achieve a balanced flavor.

Correct Brewing Time

Problem: Brewing for too short a time doesn’t allow complete flavor extraction.

Solution: Increase the brewing time to within the optimal range of 25 to 30 seconds, enabling a more complete extraction.

Regulate Water Temperature

Problem: Water that’s too cool can slow down the extraction process.

Solution: Maintain water temperature between 195 to 205 degrees Fahrenheit (90 to 96 degrees Celsius) to ensure proper extraction.

Ensure Proper Tamping

Problem: Inconsistent or too light tamping can cause uneven water flow.

Solution: Apply even and firm pressure when tamping the grounds for uniform extraction.

Use the Right Dose of Coffee

Problem: Using too little coffee in relation to water can cause under-extraction.

Solution: Measure and use the correct amount of coffee for your specific espresso machine and cup size.

Maintain Your Equipment

Problem: Malfunctioning or poorly calibrated equipment can contribute to under-extracted espresso shots.

Solution: Regular espresso machine maintenance, cleaning, and calibration ensure optimal performance.

Choose Quality Coffee Beans

Problem: Stale or low-quality beans result in lackluster flavor.

Solution: Select fresh, high-quality beans and store them properly to preserve their flavors.

Experiment and Taste Test

Consideration: Espresso preparation is both a science and an art, and preferences may vary.

Solution: Experiment with different variables and taste tests and adjust according to personal preferences and the unique characteristics of the coffee beans.

By understanding and controlling these variables, one can achieve a well-extracted espresso that sings with flavor and complexity.

What Does Under-Extracted Espresso Taste Like?

Under-Extracted espresso is a common issue that many coffee enthusiasts encounter. It results from a process where the optimal flavors and oils are not fully pulled from the coffee grounds during the espresso extraction phase. So, what does this under-extracted espresso taste like, and how can we recognize it?

When under-extracted espresso occurs, the resulting beverage usually exhibits a sour taste. This is because the initial phase of espresso extraction pulls out the acids and bright flavors from the coffee grounds. If this process is cut short or performed too quickly, the final product will lack the balance of essential flavors for a perfect espresso.

Some common characteristics of under-extracted espresso include:

  • Sourness: The prevalent acidic taste often comes across as sharp and unbalanced.
  • Weak Body: Lacking the full range of flavors, the coffee may feel thin or watery in the mouth.
  • Lack of Complexity: Missing the deep notes extracted later in the process, the espresso will lack richness and depth.

The problem of under-extraction often arises due to various factors, such as using a grind that’s too coarse, a short extraction time, or incorrect water temperature. It’s a phenomenon closely related to the art of espresso extraction, where precision and control are vital. 

To avoid the sour and thin taste of under-extracted espresso, following the proper grind size, using fresh beans, ensuring the right water temperature, and adhering to the correct extraction time are crucial.

Understanding the taste of under-extracted espresso is essential for baristas and home coffee makers. Recognizing the signs of under-extraction espresso can lead to adjustments in the brewing process that enhance the overall flavor profile. Coffee lovers can always ensure a full-bodied, rich, and satisfying cup by focusing on proper espresso extraction techniques.

Espresso Extraction

Final Musings

In the exciting world of espresso brewing, understanding the intricacies of over-extraction vs. under-extraction plays a vital role in making the perfect cup. While over-extraction leads to bitterness, under-extraction creates a sour and thin taste that lacks depth. 

Neither of these results is desirable, but recognizing the signs can help you pinpoint what needs to be adjusted.

The question of how to fix under-extracted espresso is not merely a matter of taste preference but a pathway to espresso mastery. The sour taste of under-extraction can be corrected by focusing on the correct grind size, proper tamping techniques, and optimal extraction time. The harmony between these variables is the key to transforming a mediocre cup of espresso into a delightful, complex experience.

Investing in quality equipment, practicing with different variables, and paying close attention to the taste will guide you in the right direction. Always remember that perfection in espresso is not about rigid rules but rather a delicate balance that considers both the science and the art of brewing.

Whether you are a professional barista or a home enthusiast, understanding how to fix under-extracted espresso and recognizing the difference between over-extraction vs. under-extraction equips you with the knowledge and skills needed to create exceptional espresso every time. 

Continual learning and experimentation will enhance your brewing skills and deepen your appreciation for the complex world of espresso.