How to Fix Under Extracted Espresso

How to Fix Under Extracted Espresso

As a coffee lover, pulling an espresso shot only to find it’s under-extracted can be frustrating. That sour, weak, and thin taste is far from the rich and balanced flavor you’re aiming for. Luckily, I’ve been through the same trial and error, and I’m here to share how you can fix under-extracted espresso and get it just right. After many experiments, I’ve learned what adjustments you can make to improve your espresso.

What is Under-Extraction?

Under-extraction occurs when water passes through the coffee grounds too quickly, resulting in weak, sour espresso. This happens because the water doesn’t have enough time to extract the soluble flavors from the coffee. On the flip side, over-extraction leads to a bitter, overly strong espresso. The trick is to find the right balance.

Key signs of under-extracted espresso:

  • Sour or sharp acidity: The espresso tastes sour, but not in a bright or pleasant way.
  • Thin body: A well-extracted espresso has a rich, syrupy texture, but under-extracted espresso feels watery.
  • Pale crema: The crema on top should be thick and golden-brown. A pale, thin crema is a sign of under-extraction.

Now that we know what under-extraction looks like, let’s explore how to fix it by tweaking a few key factors.

1. Adjust the Grind Size

One of the most crucial factors in espresso extraction is the grind size. Espresso requires a fine grind, and if the grind is too coarse, water flows through too quickly, leading to under-extraction.

When I started making espresso, I didn’t fully grasp how much a slight adjustment to the grind could affect the result. If your espresso tastes thin or sour, the first thing to do is grind your coffee finer. A finer grind increases surface area, giving the water more opportunity to extract the flavors. However, be cautious not to grind too fine, as this can lead to over-extraction.

Quick tip: Make small adjustments to the grind size, one notch finer at a time, and test each shot. You’ll notice improvements as you get closer to the ideal grind.

2. Tweak Your Brew Ratio

The brew ratio, or the amount of coffee to water, plays a big role in fixing under-extracted espresso. The typical espresso ratio is 1:2, meaning 18 grams of coffee should yield around 36 grams of espresso. If your shot is under-extracted, you may be using too little coffee or too much water.

I recommend experimenting with your coffee dose by slightly increasing it. This gives the water more coffee to extract from. Alternatively, you can reduce the yield (the amount of espresso produced) for a more concentrated shot.

When I struggled with under-extraction, tweaking the brew ratio was a game-changer. If you aren’t already using a scale to measure your coffee and water, now’s a great time to start. Consistency is key when dialing in the perfect espresso.

3. Check Your Water Temperature

Water temperature is another important variable in espresso extraction. If the water is too cool, it won’t properly extract the coffee’s flavors, leading to under-extraction. Ideally, your water temperature should be between 195°F and 205°F (90°C to 96°C).

I realized my machine was brewing too cool, which was causing sourness in my shots. If your espresso machine doesn’t allow you to adjust the temperature, ensure the machine is fully warmed up before pulling your shot. Some machines take a little longer to reach the correct temperature, so patience pays off here.

If your machine does have adjustable temperature settings, try increasing the temperature by a few degrees to improve flavor, but be careful—water that’s too hot can lead to over-extraction.

4. Fine-Tune Your Tamping Pressure

Tamping is the process of compressing the coffee grounds into the portafilter. If you tamp too lightly, water flows through too quickly, causing under-extraction. Conversely, tamping too hard can lead to over-extraction.

In my early days of espresso making, I didn’t pay enough attention to tamping, and I learned that an uneven or light tamp can ruin the shot. Ideally, you want to apply around 30 pounds of pressure. The tamp should be firm and even, creating a smooth surface for the water to flow through.

Pro tip: To practice your tamping pressure, try pressing down on a bathroom scale with your portafilter until you reach about 30 pounds. With time, you’ll develop a feel for the right pressure.

5. Adjust Your Shot Time

Shot time, or how long it takes to pull your espresso, is another factor that impacts extraction. The ideal shot time is usually between 25 and 30 seconds. If your shot pulls too quickly, in under 20 seconds, it’s a sign of under-extraction.

If this happens, try grinding the coffee finer, increasing the dose, or tamping more firmly. These adjustments will slow down the water flow and give it more time to extract the flavors.

At first, I used to rush my shots, not realizing how much an extra few seconds could change the outcome. Now, I always keep an eye on the timer to ensure my shots pull within the recommended range.

6. Use Fresh Coffee Beans

The freshness of your coffee beans is an often overlooked factor in espresso extraction. Coffee loses its flavor and complexity over time, so even the best brewing techniques can’t save stale beans. Freshly roasted beans have more oils and soluble compounds, leading to better extraction.

I used to keep my beans around for too long before realizing the difference fresh beans make. Now, I use beans roasted within the past two weeks, and the improvement in flavor is dramatic.

Conclusion: The Perfect Shot is Within Reach

Fixing under-extracted espresso is all about fine-tuning the variables—grind size, brew ratio, water temperature, tamp pressure, and shot time. Although it may seem tricky at first, with practice, you’ll start to see how each adjustment influences your final shot.

If your espresso tastes sour or weak, don’t be discouraged! Use it as an opportunity to learn and refine your process. With time and attention to detail, you’ll soon be pulling rich, balanced espresso shots that rival your favorite café.

Happy brewing!

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