Espresso problems: Is it your technique or your beans?

There’s nothing quite like the ritual of pulling a perfect espresso shot. The aroma, the sight of the syrupy liquid, the promise of a rich and balanced flavor. But there’s also nothing more frustrating than when it goes wrong. The shot gushes out in seconds, tasting sour and weak, or it chokes the machine, dripping out a bitter, burnt liquid. In these moments, every home barista asks the same question: is it me, or is it the coffee? This is a critical distinction. Understanding whether your espresso problems stem from a flaw in your technique or an issue with your beans is the key to consistent, delicious coffee. This guide will walk you through a systematic process to diagnose your shots and finally solve your espresso woes.

The usual suspects: Common espresso problems

Before we can fix the problem, we need to accurately describe it. Most bad espresso shots fall into a few common categories. Identifying which one you’re experiencing is the first step in the diagnostic process. Pay close attention not just to the taste, but also to what you see and hear as the shot pulls. Each symptom provides a clue pointing toward the root cause.

The fast, sour shot (under-extraction): This is perhaps the most common issue for beginners. The espresso flows out of the portafilter quickly, often in less than 20 seconds, and looks pale and watery. The crema is thin and dissipates quickly. The taste is overwhelmingly sour, acidic, and lacks sweetness or body. It can taste grassy or lemony in an unpleasant way.
The slow, bitter shot (over-extraction): The opposite problem. The shot takes a long time to start, maybe 10-15 seconds, and then slowly drips out. The total shot time can exceed 35-40 seconds. The stream may be very thin or even break apart. While the color might look dark, the taste is harsh, bitter, ashy, and dry, leaving an unpleasant feeling in your mouth.
Channeling: This is when water finds a path of least resistance through the coffee puck instead of saturating it evenly. You might see tiny jets of water spraying from the portafilter (if using a bottomless one). The shot will be a messy mix of both under-extracted and over-extracted flavors, tasting simultaneously sour and bitter, with a thin body.

Recognizing these symptoms is crucial. A fast, sour shot points to water moving through the coffee too easily, while a slow, bitter shot indicates the water is struggling to get through. Channeling tells you the puck’s integrity is compromised. Now, let’s explore why these things happen.

Analyzing your technique: The barista’s role

More often than not, the solution to your espresso problems lies in your own hands. Technique is a chain of events where one weak link can ruin the final result. Before you blame your expensive bag of single-origin beans, take an honest look at your process. Inconsistency is the enemy of good espresso, so mastering these steps is non-negotiable.

The core of your technique is what baristas call “puck prep”. This is everything you do to prepare the ground coffee in the portafilter for extraction.

Grind size: This is your primary tool for controlling shot time. If your shot is too fast and sour, you need to grind finer. This creates more surface area and a more compact puck, slowing down the water. If your shot is too slow and bitter, you need to grind coarser to allow water to pass through more easily. Make one small adjustment at a time.
Dose: This is the amount of dry coffee grounds you use. It’s crucial to use a scale to measure your dose every single time. A gram more or less can significantly alter the shot. An inconsistent dose makes it impossible to tell if changes in your shot are due to your grind adjustment or a different amount of coffee.
Distribution: After grinding into your portafilter, the grounds are often clumpy and unevenly distributed. If you tamp this, you create dense and loose spots in the puck. Water will rush through the loose spots, causing channeling. Use a distribution tool (WDT) or a simple needle to break up clumps and evenly rake the grounds.
Tamping: The goal of tamping is not to press as hard as you can, but to apply firm, even pressure to create a level and uniformly compressed puck. An uneven tamp will encourage channeling from the moment the water hits the coffee.

If you aren’t precisely controlling these four variables, especially dose and grind, you are essentially flying blind. It’s almost certain your problems are technique-related.

Scrutinizing the beans: When the coffee is the culprit

You’ve perfected your puck prep. Your dose is consistent to a tenth of a gram, you distribute meticulously, and your tamp is perfectly level. You’ve adjusted your grind size again and again, but the coffee still tastes… off. Now, it’s time to look at the beans themselves. Even a world-champion barista cannot pull a delicious shot from bad beans.

The most significant factor here is freshness. Coffee is a perishable product. After roasting, beans release CO2 and volatile aromatic compounds. This process is great for the first few days (coffee needs to “de-gas”), but after a few weeks, the magic starts to fade.

Stale beans (roasted > 1 month ago): Beans that are too old have lost most of their CO2. This gas is crucial for creating pressure resistance during extraction and forming rich, stable crema. Shots from stale beans will gush out quickly, even at a very fine grind setting. They will produce little to no crema and taste flat, woody, or papery.
Extremely fresh beans (roasted < 5 days ago): On the other hand, beans that are too fresh can have an excess of CO2. This can cause erratic extractions, excessive crema that tastes gassy, and prevent the water from properly saturating the grounds, leading to sourness. Most beans hit their sweet spot between 7 and 21 days after roasting.

Beyond freshness, consider the roast level and quality. A very light roast can be extremely difficult to extract properly and may taste intensely acidic unless your technique and equipment are flawless. Conversely, a very dark, oily roast can taste bitter and roasty no matter how perfectly you pull the shot. Finally, some beans are simply low-quality or have roast defects, resulting in unpleasant flavors like rubber, smoke, or baked bread that no amount of skill can fix.

A systematic diagnostic approach

The key to troubleshooting is to change only one variable at a time. This scientific method allows you to isolate the problem instead of randomly trying different things. Start by assuming the problem is your technique, as it is the most common culprit and the one you have the most control over.

Follow these steps:

Check the roast date. Is it within the ideal window (e.g., 7-21 days)? If it’s over a month old, your beans are likely the primary issue. If it’s too fresh, let them rest for a few more days.
Lock in your variables. Choose a dose and stick with it (e.g., 18g). Perfect your distribution and tamping to be as consistent as possible. Decide on a target yield (e.g., 36g).
Adjust the grind. Now, your grind size is the only thing you will change. Pull a shot, timing it from the moment you press the button to when you hit your target yield.
Taste and evaluate. Is it too fast and sour? Grind finer. Is it too slow and bitter? Grind coarser. Repeat this process, making small adjustments, until your shot time is in the 25-35 second range.
Final taste assessment. Once your shot parameters (dose, yield, time) are correct, give it a final taste. If it’s balanced and delicious, you’ve succeeded! If it still has distinct off-flavors despite the balanced extraction, now you can confidently blame the beans.

Here is a simple table to guide your diagnosis:

Symptom	Likely Technique Cause	Likely Bean Cause	Solution
Fast, Sour Shot (Under-extracted)	Grind is too coarse. Dose is too low. Poor distribution/channeling.	Beans are very stale (over 1 month old).	1. Grind finer. 2. Ensure consistent dose. 3. Check bean freshness.
Slow, Bitter Shot (Over-extracted)	Grind is too fine. Dose is too high. Tamping too hard (less common).	Beans are extremely fresh (under 5 days old), causing choking. Very dark, oily roast.	1. Grind coarser. 2. Ensure consistent dose. 3. Let fresh beans rest.
Sour AND Bitter Shot (Channeling)	Uneven distribution (clumps). Uneven tamp. Grind is too fine, forcing channeling.	Less likely to be a bean issue, but very brittle dark roasts can produce fines that promote channeling.	1. Focus on WDT/distribution. 2. Ensure a level tamp. 3. Try grinding slightly coarser.
No Crema, Flat Taste	Water temperature too low.	Beans are stale. This is the #1 cause.	1. Buy freshly roasted beans. 2. Ensure your machine is properly heated.

Conclusion: The path to better espresso

The journey to mastering espresso is a process of elimination. By understanding the distinct roles that technique and beans play, you can move from a state of frustration to one of control. In most cases, the path to a better shot begins with a critical look at your own workflow: consistent dosing, meticulous distribution, and methodical grind adjustments. This is fantastic news, because your technique is something you can improve for free, right now. However, it’s equally important to recognize the limitations of your raw materials. No amount of skill can resurrect stale, old beans. By adopting a systematic approach, you can confidently diagnose your espresso, solve problems efficiently, and spend less time guessing and more time enjoying truly exceptional coffee.