In practice, however, pulling off that perfect shot of espresso can be a fuss. Each cup of espresso from your favourite specialty cafe is likely brilliantly brewed and balanced. Yet, it's a different story at home. You follow the recipe to a T but still find yourself asking, Why is my espresso bitter

We’re here to help you pinpoint the culprit of your bitter coffee, from over-extraction to stale beans. 

What causes bitter espresso? 

Contrary to popular belief, bitterness does not derive from caffeine alone. Espresso’s flavour, aroma, and effect originate from countless compounds, and around 30 of them are bitter.

The interaction of these compounds—a process known as extraction—is what’s actually behind espresso’s complex taste. Similar to leaving your tea steeping for ages, too much of a bitter taste in espresso stems from an unbalanced performance in its symphony of flavours.

An overview of over-extraction

Coffee extraction occurs when the espresso machine pushes hot water through coffee grounds, prompting a delicate drip of espresso into your demitasse. However, over-extraction can lead to an astringent flavour, spoiling your espresso and coffee break.

Why does over-extraction occur?

Too hot or too cold water temperature 

Ever wonder why your extracted coffee tastes too bitter or acidic? It might be due to incorrect extraction time. It’s best to brew your espresso at a consistent temperature between 92°C and 96°C., Water that’s too hot hurries extraction and begets bitterness, while overly cold water causes under-extraction and an acidic aftertaste.

Old or stale beans 

Coffee beans lose natural oils and gases over time, resulting in a cup of espresso you won’t fancy. 

Here’s how to keep your beans at tip-top quality and optimal taste:

● Grind coffee beans just before brewing for the freshest aroma and flavour

● Store in an airtight container to preserve quality 

● Use within the recommended time frame

We also recommend checking the “roasted on” date of your beans. Grinding and brewing your beans too early can overpower your cup with a harsh taste. Always try to keep coffee beans fresh for a balanced, bitter-free morning brew.

Brewing blunders that cause bitterness 

Aside from water temperature and beans, several steps along the way can make your espresso sink or swim. 

Grinding too finely 

One of the most common mistakes in brewing espresso happens before it even touches the portafilter: over-grinding the coffee beans. Finer grounds means quicker extraction, which brings out a disproportionate amount of bitter compound flavours., Make sure you are choosing the right coffee grind size based on the machine or coffee brewing technique you are following. 

Using dark roasts incorrectly 

Before you grind or tamp, factor in the type of coffee bean in your pantry. Dark roast—the top pick for espresso—extracts at a faster rate than light roast due to its longer roasting process. Instead, opt for a lighter roast to achieve your ideal flavor profile. 

How to fix a bitter espresso shot

As a strong yet small-volume coffee drink, espresso is more susceptible to minor changes. Consistency and attention to detail are key.

If bitterness won’t back off, no matter what you try, problem-solve with these pointers: 

● Adjust your extraction time — Espresso needs slow, even saturation to strike the ideal flavour balance and a velvety texture. So, adjust your extraction time based on flavour. For example, if your espresso is too bitter, try a shorter extraction time in your next brew. 

● Experiment with dose and yield — Change one variable at a time in your espresso study. You’ll find that the type of coffee drink you make (e.g. plain espresso or flat white) will require specific adjustments to your water-coffee ratio.

● Try a new bean or roast profile — Roast type, as well as bean brand and origin, influence espresso extraction and taste. Try different options to find the bean that best suits your preferences.

● With time, you’ll discover how to make—and consistently replicate—a smooth and satisfying shot of espresso.

Pro tips for a smoother espresso 

You can make the extraction process and your espresso as smooth as possible with regular equipment maintenance. Routinely cleaning your espresso machine with a brush and hot water goes a long way towards performance and taste. 

Further, utilise scales and a timer to perfect your yield-dose ratio and extraction time. 

With these expert tips, bitter espresso will soon be history in your household. 

Bid adieu to bitter espresso with Sage 

To achieve the perfect flavour profile in your roast without making your espresso too bitter, follow our Sage advice—and browse our variety of espresso machines to treat yourself to the finest equipment on the market.

At Sage, we believe your espresso should be complex in flavour, not in practice. Lean into the ritual and craft each cappuccino, latte, and simple shot of espresso with ease with our professional-quality kitchen appliances.

Sources: 

1. Bean Scene. How to craft the perfect espresso. https://www.beanscenemag.com.au/how-to-craft-the-perfect-espresso/

2. Coffee Geek. New to Home Espresso? Start Here. https://coffeegeek.com/blog/beginners/new-to-home-espresso-start-here/

3. Daily Coffee News. Plunger, Espresso, Filter? Just Because Your Coffee is Bitter, Doesn’t Mean It’s ‘Stronger.’ https://dailycoffeenews.com/2022/08/31/plunger-espresso-filter-just-because-your-coffee-is-bitter-doesnt-mean-its-stronger/

4. National Library of Medicine. Analysis of Volatile Compounds in Coffee Prepared by Various Brewing and Roasting Methods. https://pmc.ncbi.nlm.nih.gov/articles/PMC8230519/

5. Perfect Daily Grind. Coffee Extraction & How It Helps Create The Perfect Cup. https://perfectdailygrind.com/2018/11/understanding-coffee-extraction-for-your-perfect-cup/

6. Perfect Daily Grind. How can consumers make better espresso at home? https://perfectdailygrind.com/2023/04/how-can-consumers-make-better-espresso-at-home/

7. Perfect Daily Grind. How does temperature stability affect espresso extraction? https://perfectdailygrind.com/2022/06/how-does-temperature-stability-affect-espresso/

8. Perfect Daily Grind. Manual espresso machines: How to pull the perfect shot. https://perfectdailygrind.com/2023/11/manual-espresso-machines-perfect-shot/

9. Science Direct. Identification of compounds that enhance bitterness of coffee brew. https://www.sciencedirect.com/science/article/abs/pii/S0308814623002911

10. The Tasty Bite. Bitter vs. Sour Espresso Explained (And How To Fix It). https://www.thetastybiteblog.com/bitter-vs-sour-espresso-explained/

11. The Tasty Bite. Why Is My Espresso Coffee Bitter? How to Fix the Bitter Taste.  https://www.thetastybiteblog.com/why-is-my-espresso-coffee-bitter-how-to-fix-the-bitter-taste/