How to Fix Under Extracted Espresso

As a coffee enthusiast, there's nothing more frustrating than pulling an espresso shot and realizing it's under-extracted. You know the taste—sour, thin, and lacking the rich, complex flavors that define a perfect espresso. If you’ve ever struggled with under-extracted espresso, don’t worry—you're not alone. I’ve been there myself, and I’m here to share what I’ve learned about how to fix it. Through trial, error, and plenty of coffee, here’s how you can get your espresso just right.

What is Under Extraction?

Before diving into how to fix under-extracted espresso, it's important to understand what under-extraction is and why it happens. Under-extraction occurs when water flows too quickly through the coffee grounds, not spending enough time to properly extract all the flavors. As a result, the espresso tastes weak, overly acidic, and often sour. On the other hand, over-extracted espresso tastes too strong and bitter, so the goal is to find the perfect balance.

Key signs of under-extracted espresso include:

• Sourness or sharp acidity: A sour taste is usually the most obvious sign of under-extraction.
• Thin body: Proper espresso has a rich, syrupy texture. If it feels watery, it’s likely under-extracted.
• Pale crema: Crema should be thick and golden-brown. If it’s pale and thin, that’s another sign of under-extraction.

Now that you understand the problem, let’s explore how to fix it. Several factors affect espresso extraction, and adjusting these can help you achieve that perfect shot.

Adjust the Grind Size

Grind size is one of the most critical factors in espresso extraction. Espresso requires a fine grind, but if the coffee is too coarse, water will pass through it too quickly, leading to under-extraction.

When I first started making espresso, I underestimated how much a small change in grind size could affect the taste. If your shot is sour or thin, the first step is to grind your coffee finer. This increases the surface area of the coffee, allowing the water to extract more flavors. Be cautious, though—grinding too fine can lead to over-extraction.

Pro tip: Make small adjustments, one notch finer at a time, and test each shot. You’ll notice the flavor shift as you approach the right grind size.

2. Tweak Your Brew Ratio

Another crucial factor in fixing under-extracted espresso is adjusting your brew ratio. Brew ratio refers to the proportion of coffee grounds to water. A typical espresso brew ratio is 1:2, meaning 18 grams of coffee should yield around 36 grams of espresso. If your shot is under-extracted, you might be using too little coffee or too much water.

Try experimenting with the dose—the amount of coffee you’re using. Increasing the dose slightly allows the water to interact with more coffee, which can help extract more flavor. Alternatively, you can decrease the yield (the amount of espresso produced) for a more concentrated shot.

Pro tip: Weighing your coffee and espresso is key. Using a small scale helps ensure consistency and allows you to fine-tune the brew ratio for the best results.

3. Check Your Water Temperature

Water temperature plays a significant role in espresso extraction. If the water is too cool, it won’t extract enough flavor from the grounds, resulting in under-extraction. Ideally, water temperature for espresso should be between 195°F and 205°F (90°C to 96°C).

When I first learned about water temperature, I realized my espresso machine wasn’t hot enough, causing my shots to taste sour. If your machine doesn’t allow you to adjust the temperature, make sure it’s fully warmed up before pulling a shot. Some machines take longer to heat up, so patience is key.

If your machine does have adjustable temperature settings, try increasing the temperature slightly to see if it improves the flavor of your espresso. Remember, making gradual changes prevents over-extraction.

4. Dial in Your Tamp Pressure

Tamping is another vital step in espresso brewing. If you tamp the grounds too lightly, water will pass through them too quickly, leading to under-extraction. On the flip side, tamping too hard can result in over-extraction.

In my early days of making espresso, I didn’t pay much attention to tamping and quickly learned that a light or uneven tamp can ruin a shot. Ideally, you should apply about 30 pounds of pressure when tamping, ensuring it’s firm and even to create a flat surface for the water to flow through.

Pro tip: Practice tamping with a bathroom scale. Press down with the tamper until you reach 30 pounds of pressure. Over time, you’ll develop a feel for the right amount of force.

5. Adjust Your Shot Time

Shot time is another factor that impacts extraction. The ideal shot time for espresso is between 25 and 30 seconds. If your shot pulls too quickly—under 20 seconds—it’s likely under-extracted.

If your shot pulls too fast, try grinding the coffee finer, increasing the dose, or tamping more firmly. These adjustments slow down the water flow, giving it more time to extract the flavors.

When I started making espresso, I often rushed the process, unaware that a few extra seconds could make such a big difference. Now, I always keep an eye on the timer to ensure my shot pulls within the optimal time range.

6. Fresh Coffee Matters

One factor often overlooked in espresso extraction is the freshness of your coffee beans. Coffee loses its flavor and complexity as it ages, so using stale beans can lead to under-extracted, dull shots.

In my early espresso days, I didn’t realize the importance of fresh beans. Now, I make sure to use coffee that’s been roasted within the past two weeks. Freshly roasted beans contain more oils and soluble compounds, which enhance flavor extraction.

Conclusion: The Perfect Shot is Within Reach

Fixing under-extracted espresso requires fine-tuning several variables—grind size, brew ratio, water temperature, tamp pressure, and shot time. It might seem overwhelming at first, but with practice, you’ll learn how each factor influences your espresso shot. Don’t be discouraged by sour or thin espresso; instead, use it as an opportunity to improve.

As I’ve discovered throughout my espresso journey, small adjustments can lead to significant improvements. By paying attention to the details and practicing regularly, you’ll soon be pulling rich, well-balanced espresso shots that rival your favorite café. Happy brewing!