Espresso is a beloved coffee drink, but it can sometimes turn out bitter, ruining the experience. Bitterness in espresso can come from several factors, including brewing techniques, bean quality, and equipment issues. This article explores the common reasons behind bitter espresso and how to fix them.
Understanding Espresso Bitterness
Bitterness is a natural part of coffee’s flavor profile, but excessive bitterness means something went wrong during extraction. Espresso should balance sweetness, acidity, and bitterness. When bitterness overpowers other flavors, it’s often due to over-extraction, poor bean quality, or incorrect brewing parameters.
The Role of Coffee Compounds
Coffee contains hundreds of compounds that influence taste. Chlorogenic acids and caffeine contribute to bitterness. Over-extraction pulls too many of these compounds, making the espresso harsh. Under-extraction, on the other hand, can lead to sourness. The key is finding the right balance.
Common Causes of Bitter Espresso
Several factors can make espresso taste bitter. Let’s break them down one by one.
Over-Extraction
Over-extraction is the most common cause of bitterness. It happens when water spends too much time in contact with the coffee grounds, dissolving unwanted bitter compounds.
How Over-Extraction Happens
Grind Size Too Fine: Fine grinds increase surface area, causing over-extraction.
Brew Time Too Long: Espresso should extract in 25-30 seconds. Longer times lead to bitterness.
Too Much Pressure: High pressure forces water through coffee too quickly, extracting harsh flavors.
Fixing Over-Extraction
- Use a coarser grind to slow extraction.
- Adjust brew time to 25-30 seconds.
- Check your machine’s pressure (ideally 9 bars).
Poor Coffee Bean Quality
Low-quality or stale beans often taste bitter. Fresh, high-quality beans have balanced flavors.
Signs of Bad Beans
Dark, Oily Beans: Over-roasted beans are bitter.
Stale Beans: Coffee loses freshness after 2-4 weeks post-roast.
Low-Grade Beans: Cheap beans may have defects that increase bitterness.
Choosing the Right Beans
- Buy freshly roasted beans (within 2 weeks).
- Opt for medium roasts for balanced flavor.
- Avoid overly dark roasts if bitterness is an issue.
Incorrect Water Temperature
Water that’s too hot burns the coffee, creating bitterness. The ideal temperature is between 195°F and 205°F (90°C-96°C).
How Temperature Affects Extraction
Too Hot (>205°F): Extracts bitter compounds.
Too Cold (<195°F): Leads to under-extraction and sourness.
Adjusting Temperature
- Use a thermometer to check water temperature.
- Preheat your machine to stabilize heat.
- Adjust boiler settings if possible.
Dirty or Old Equipment
Residue from old coffee oils can make espresso taste bitter. Regular cleaning is essential.
Cleaning Tips
- Backflush the machine daily.
- Clean the portafilter and basket after each use.
- Descale monthly to prevent mineral buildup.
Incorrect Dose and Tamping
Too much coffee or uneven tamping can cause uneven extraction, leading to bitterness.
Proper Dosing and Tamping
- Use 18-20 grams of coffee for a double shot.
- Tamp evenly with 30 lbs of pressure.
- Avoid over-packing the portafilter.
Advanced Troubleshooting
If bitterness persists, deeper issues may be at play.
Machine Calibration Issues
Espresso machines need proper calibration for consistent results.
Checking Pressure and Flow
- Test pump pressure (should be 9 bars).
- Ensure consistent water flow.
- Adjust grind size if channeling occurs.
Bean Freshness and Storage
Even good beans can turn bitter if stored improperly.
Best Storage Practices
- Keep beans in an airtight container.
- Store in a cool, dark place.
- Avoid freezing unless vacuum-sealed.
Conclusion
Bitterness in espresso usually stems from over-extraction, poor beans, or equipment issues. By adjusting grind size, brew time, and machine settings, you can achieve a balanced shot. Always use fresh, high-quality beans and keep your equipment clean. With these fixes, your espresso should be smooth and flavorful.
Experiment with different variables to find your perfect brew. Happy brewing!
Related topics:
How Many Grams of Coffee to Make Espresso?
How Much Pressure to Make Espresso?
How Do You Make Espresso Powder?