Have you ever brewed a shot of espresso, eagerly anticipating that first, rich sip, only to be greeted with a disappointing, sour punch? I still remember my first few weeks with my shiny new espresso machine—each shot was sourer than the last, and I was ready to give up. But I didn’t. After a lot of trial and error, I figured out exactly what adjustments needed to be made to transform those overly acidic shots into smooth, well-balanced espresso. If you’ve been struggling with the same issue, fear not. Let me share what I've learned, so you too can banish that sourness for good. Explore the ease of use and versatility in our DeLonghi Eletta Explore Espresso Machine with Cold Brew Review
What Causes Sour Espresso?
Before we jump into solutions, it’s helpful to understand why espresso ends up sour in the first place. Sourness usually means under-extraction, which simply means the coffee hasn’t had enough time to fully develop its flavors. When under-extracted, acidic compounds in the coffee dominate, resulting in a sharp, unpleasant sourness. A few common culprits can contribute to under-extraction, but once you understand them, fixing the problem becomes a lot easier. Discover the advanced frothing capabilities in our DeLonghi Dinamica Automatic Coffee & Espresso Machine Review
Adjusting Grind Size
One of the primary reasons for sour espresso is an incorrect grind size. When I first started out, I learned the hard way that if your grounds are too coarse, water flows through too quickly, resulting in under-extraction and a sour flavor. I can vividly recall my excitement turning into dismay with every sour sip—until I learned to fine-tune my grind size. Compare features and performance in our DeLonghi Magnifica Evo Espresso Machine with Frother Review
How to Fix It:
Try making your grind size finer. Adjust your grinder to a smaller setting, but make incremental changes. A finer grind means there’s more surface area for the water to extract flavors from, leading to a more balanced espresso. Test each shot and observe the results to find that perfect sweet spot. See how these two models stack up in our DeLonghi Magnifica Evo vs Philips 4300

Optimize Water Temperature
The temperature of your water is another crucial factor. If the water is too cool, it won't extract the flavors properly from the coffee grounds, resulting in an underwhelming and sour shot. I remember the day I finally realized my machine wasn’t heating properly—and once I fixed that, the improvement in taste was night and day. Find out the key differences in our DeLonghi Magnifica Evo vs Philips 2200
How to Fix It:
Water temperature for espresso should ideally be between 195°F and 205°F (90°C to 96°C). Use a thermometer to check your machine’s temperature or use the temperature control settings if available. Make sure you let your machine heat up fully before pulling a shot—sometimes just waiting an extra minute or two can make all the difference. Explore the ease of use and versatility in our DeLonghi Magnifica Evo vs Philips 3200
Fine-Tune Brew Time
Brew time—or extraction time—is a critical factor in achieving balanced espresso. Shots that pull too quickly, often under 25 seconds, can lead to sourness. In my early days, my shots always pulled too fast, leaving me with a sour taste that made me cringe.
How to Fix It:
Time your shots carefully. The ideal extraction time for a standard espresso shot is between 25-30 seconds. If your shot finishes too quickly, try tamping the grounds more firmly or adjusting to a finer grind to slow down the water flow. Just remember, going too far could result in bitterness—it’s all about finding balance.
Check Coffee Freshness
Believe it or not, stale beans can be a major cause of sour espresso. Coffee is at its best within two to three weeks of roasting. I made the mistake of using month-old beans, only to be met with a consistently sour or flat taste.
How to Fix It:
Whenever possible, use freshly roasted beans. Always check the roast date on your coffee bag and aim to use the beans within a few weeks. If you’re not going through beans quickly, consider buying smaller batches or joining a coffee subscription to keep your supply fresh.
Measure Your Coffee Dose
The right amount of coffee in the portafilter is key to balanced espresso. Too little coffee allows water to pass through too quickly, leading to under-extraction and sour flavors. Early on, I used to eyeball my dose, and my espresso quality was inconsistent at best.
How to Fix It:
Weigh your coffee! Use a digital scale for precision. A typical dose for a single espresso shot is between 18-20 grams of coffee. If your espresso tastes sour, try slightly increasing your dose and see how it affects the extraction.
Extra Tips for Espresso Perfection
Now that we’ve addressed the main culprits of sour espresso, here are a few additional tips that helped me refine my technique over time:
Invest in High-Quality Equipment
The quality of your equipment matters more than you might think. A good burr grinder gives a more consistent grind size, resulting in better extraction. Likewise, a stable espresso machine with reliable temperature and pressure settings can make a huge difference in your shots.
Consistency is Key
I can’t stress this enough: consistency will make or break your espresso-making journey. Once you’ve dialed in the right grind size, temperature, and brew time, replicate it for each shot. Keep track of these settings—trust me, your future self will thank you.
Experiment and Adapt
Every coffee bean is different. Factors like the bean's origin, roast level, and freshness can all affect how you should brew. Don’t be afraid to experiment! Lighter roasts, for instance, often require a finer grind or longer brew time compared to darker roasts. Adapting to each type of coffee is part of the journey.
Conclusion
Fixing a sour espresso isn’t as complicated as it might seem at first. By focusing on variables like grind size, water temperature, brew time, coffee freshness, and dose, you can eliminate sourness and consistently brew rich, flavorful espresso. Remember, making espresso is a bit like an art form—it takes practice, patience, and a willingness to learn from every shot you pull. Don't be discouraged if it takes time; every successful shot makes the journey worthwhile.
Happy brewing, and may your next espresso be perfectly balanced!

FAQ
Q: Why does my espresso taste sour even though I follow all the instructions?A: Sourness often results from under-extraction. Even if you’re following the general guidelines, slight variations in grind size, water temperature, or brew time can still lead to under-extracted, sour flavors. Try making minor adjustments until you find the perfect balance.
Q: Can using older coffee beans make my espresso sour?A: Yes, stale coffee beans can result in sour espresso. Coffee loses its flavor quickly, especially after the first two to three weeks from roasting. Using freshly roasted beans is crucial to avoid sour or flat espresso.
Q: What’s the ideal water temperature for brewing espresso?A: The ideal temperature for brewing espresso is between 195°F and 205°F (90°C to 96°C). Anything below this range can lead to under-extraction and a sour taste.
Q: Should I always use a digital scale to weigh my coffee dose?A: Absolutely. Precision is key in making espresso, and eyeballing your coffee dose can lead to inconsistent results. A digital scale will help you measure the exact amount needed, resulting in more balanced extractions.
Q: What is under-extraction, and how does it affect espresso?A: Under-extraction occurs when the coffee grounds haven’t had enough contact time with the water to fully develop their flavors. This usually results in a sour, acidic taste because only the initial acidic compounds are extracted.