Pulling a great shot of espresso shouldn’t feel like a game of roulette.
As long as you know what great espresso tastes like and how to identify any problems in the cup, you’ll find that it can be predictable and extremely rewarding.
Here’s how to troubleshoot your espresso.
The Anatomy of a Great Espresso Shot
At its core, balance is the most fundamental trait of great espresso. When the sweetness, bitterness, and acidity come through clearly, you know you’ve pulled a well-balanced shot.
A common starting point is a 1:2 brew ratio with an extraction time of 25-30 seconds. Although coffee connoisseurs believe taste is the ultimate deciding factor, these are basic guidelines you can use to get started.
The key variables at play in the brewing process are grind size, dose, yield, temperature, time, and pressure. Once you learn more about how they influence what’s in the cup, you’ll realise that there’s always a logical explanation for why your espresso tastes the way it does.
Common Espresso Problems & How to Fix Them
Most espresso issues fall into three categories: under-extracted, over-extracted, or uneven. Here’s how to fix each:
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Under-extracted shots - If the espresso tastes sour or sharp, it’s likely because it is under-extracted. What causes this? Perhaps the grind is too coarse, the water temperature is not hot enough, or the brew time is shorter than required. Consider making the grind size finer, increasing the extraction time or checking if the espresso machine is properly heated.
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Overpowering shots - Does the espresso taste harsh or too bitter? You’re looking at the result of over-extraction, using too fine a grind, or using an imbalanced dose-to-yield ratio. Fix this problem by adjusting the dose-to-yield ratio, shortening the brew time, or using coarser grinds.
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Hollow shots - Those weak, watery cups that don’t resemble an espresso by a long shot are often caused by a wrong coffee-to-water ratio, channelling, or inconsistent puck preparation. To prevent hollow shots, improve the distribution and tamping, check if there’s uneven flow during extraction, or increase the coffee dose.
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Inconsistent shots - If one cup tastes great but the next is weak, and this cycle keeps repeating, you need to build a standardised routine where each step you take is the same as before. Dial in your grind regularly to maintain consistency. Lastly, warm up the espresso machine properly to avoid temperature fluctuations.
If your espresso tastes sour and bitter, channelling is a likely cause. This occurs when the coffee grounds are not evenly distributed, and tamping isn’t done properly, causing weak spots in the coffee bed. Water rushes through these spots, thereby overextracting some areas and under-extracting others.
Focus on puck preparation to avoid channelling. Distribute the coffee evenly and ensure uniformity while tamping.
Dialling in espresso can also help you identify what needs to be changed. We have created a dedicated guide to dialling in coffee that you can refer to.
When It’s Not You, It’s the Beans
With all of that being said, sometimes the fault doesn’t lie in the brewing process. The coffee you’re using may be harder to dial in for espresso. Maybe it’s no longer fresh, or it’s too fresh.
Depending on the roast level, extraction may also be affected, leading to poor-quality espresso. For instance, light roasts are great for complexity, but if not dialled in properly, they can lead to sour shots. Darker roasts, on the other hand, are easier to extract but just as easily can turn bitter.
When you use too fresh coffee (i.e. not nearly enough time has passed after roasting), it can result in gassy, inconsistent shots. And we all know that coffee that’s a little too old delivers a flat, low-crema espresso with muted flavours.
You should also experiment with single origins and blends to see which one produces a better cup of espresso.
Troubleshooting espresso is all about staying patient, changing one variable at a time, and knowing what to look for.