How to Fix Under Extracted Espresso

As a passionate coffee lover, there’s nothing more frustrating than brewing an espresso only to discover it’s under-extracted. That unpleasant sour, thin taste lacking the rich, layered flavors of a well-pulled espresso can be disappointing. But don’t worry—I’ve been in your shoes, and I’m here to help you troubleshoot and fix under-extracted espresso. Through trial, error, and numerous attempts, I’ve gathered some valuable insights to share with you.

Understanding Under Extraction

Before diving into the solutions, it’s crucial to understand what under extraction is and why it happens. Under extraction occurs when water passes through the coffee grounds too quickly, not allowing enough time to fully draw out the coffee’s soluble flavors. The result is a weak, sour, and often unpleasant cup. Conversely, over-extracted espresso can taste overly bitter and strong, so the goal is to find the sweet spot between the two.

Here are a few telltale signs of under-extracted espresso:

Sour taste or sharp acidity: A harsh, unpleasant acidity is a clear sign of under extraction.
Thin texture: A properly extracted espresso should have a rich, syrupy body. Under-extracted shots feel watery and lack depth.
Pale crema: The crema should be thick and creamy. A pale, thin crema indicates under extraction.

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

1. Fine-Tune the Grind Size

One of the most crucial factors in espresso extraction is grind size. Espresso requires a fine grind, but if the grind is too coarse, water will flow through too quickly, causing under extraction.

When I started making espresso, I underestimated how much a minor change in grind size could impact the result. If your espresso tastes sour or weak, the first step is to grind the coffee finer. This increases the surface area exposed to the water, allowing for better flavor extraction. However, be cautious—not too fine, or you risk over-extraction.

Pro Tip: Make small adjustments to your grinder, one notch finer at a time, and test each shot. You’ll start to notice improvements as you approach the ideal grind size.

2. Adjust Your Brew Ratio

Fixing under-extracted espresso may also involve tweaking your brew ratio—the balance between the amount of coffee grounds and water used. A standard espresso ratio is 1:2, meaning 18 grams of coffee will produce around 36 grams of espresso. If your shot is under-extracted, you may be using too little coffee or too much water.

Experiment with your coffee dose by slightly increasing it. This gives the water more coffee to extract flavor from. Alternatively, reducing the yield (the amount of espresso produced) will concentrate the flavors.

In my experience, adjusting the brew ratio made a noticeable difference. If you’re not already using a scale to measure your coffee and water, now’s a great time to start. This will help you maintain consistency and perfect your shot.

3. Optimize Your Water Temperature

Water temperature is another critical component in espresso extraction. If the water is too cool, it won’t properly extract flavors from the grounds, leading to under extraction. The ideal brewing temperature for espresso is between 195°F and 205°F (90°C to 96°C).

When I discovered my machine was brewing too cool, I realized it was causing the sourness in my shots. If your machine doesn’t allow for temperature adjustments, make sure it has fully warmed up before pulling a shot. Some machines need extra time to reach optimal temperatures.

If your espresso machine has adjustable temperature settings, try increasing the temperature slightly to improve the flavor. But be careful—water that’s too hot can lead to over-extraction.

4. Fine-Tune Your Tamping Pressure

Tamping, the process of compressing coffee grounds in the portafilter, plays a pivotal role in espresso extraction. If you tamp too lightly, water will flow through too quickly, resulting in under extraction. Tamping too hard, on the other hand, could cause over-extraction.

Early on, I didn’t realize the importance of proper tamping pressure. Aim to apply around 30 pounds of pressure, pressing firmly and evenly to create a flat surface for the water to pass through.

Pro Tip: Practice tamping on a bathroom scale to get a feel for what 30 pounds of pressure feels like. With practice, you’ll develop a more consistent tamping technique.

5. Adjust the Shot Time

Shot time is another critical variable that affects extraction. Ideally, an espresso shot should pull between 25 and 30 seconds. If your shot pulls faster (in under 20 seconds), it’s likely under-extracted.

To slow down the shot time, consider grinding the coffee finer, increasing the coffee dose, or tamping with more pressure. These adjustments will slow the water flow, allowing more time for flavor extraction.

I used to rush the process when I first started, unaware of how much a few extra seconds could change the result. Now, I keep a close eye on the timer to ensure my shots pull within the recommended range.

6. Use Fresh Coffee Beans

One commonly overlooked factor in espresso extraction is the freshness of the beans. Coffee beans start to lose their flavor and complexity shortly after roasting. If your beans are stale, no amount of perfect brewing technique will save your shot from under-extraction.

I learned this the hard way when I used older beans. Now, I make sure to use coffee roasted within the past two weeks, and the difference is striking. Fresh beans contain more oils and soluble compounds that contribute to better extraction and flavor.

Conclusion: Achieving the Perfect Shot

Fixing under-extracted espresso comes down to fine-tuning various factors—grind size, brew ratio, water temperature, tamping pressure, and shot time. While it may seem challenging at first, with practice, you’ll begin to understand how each adjustment influences the final shot.

Rather than being discouraged by sour or thin espresso, view it as an opportunity to improve. Through small changes and regular practice, you’ll soon be pulling rich, balanced espresso shots that rival your favorite café. Happy brewing!