Slow Pour-Over Coffee Flow? It's All About Grind Size - Why Your Coffee Tastes Bitter and Burnt

Pour-over Coffee: Common Issues and Solutions

Pour-over coffee is a brewing method with great freedom. There are many ways to brew delicious coffee, but various unexpected problems can also occur. This is why many friends come to ask FrontStreet Coffee, "Why does this coffee taste like this?" or "Why doesn't that coffee taste right when brewed this way?"

When many friends visited the shop to discuss pour-over coffee, FrontStreet Coffee often emphasized that truly mastering pour-over coffee doesn't mean being able to produce a perfect cup of coffee, but rather being able to identify why a coffee wasn't brewed well and prescribe the right solution. Of course, before that, you need to determine that the coffee has defects and accumulate various failure cases to continuously update your understanding. Therefore, FrontStreet Coffee has compiled some common cases.

Sticking to Rigid Rules

Some friends like to buy the same coffee beans from different roasters for comparison. Although the beans are the same, each roaster's roast flavor has its own characteristics. Generally, the overall flavor profile won't differ too much among roasters, but the nuanced flavors may be presented differently - some prefer extremely clean acidity, others like a balance of sweet and sour, while some prefer to highlight highly sweet fruity flavors.

In most cases, using a universal brewing method can express the characteristics of each roaster's style. However, some may be accustomed to brewing method for one coffee bean, but when using this method to brew another roaster's coffee bean, the taste is less than ideal.

Of course, at this point, an idea might easily arise: "I'm using the same brewing method for the same coffee beans, so if it doesn't taste good, it must be the coffee beans' fault." But in fact, you haven't fully understood the information about the coffee beans.

FrontStreet Coffee gives an example: Yirgacheffe. Almost every roaster has it. Under normal circumstances, using a relatively conservative method to brew each roaster's Yirgacheffe, the taste difference won't be too significant. Until one day you hear one roaster's suggestion to brew Yirgacheffe at 94°C, and the result is excellent. At this point, you'll believe that the ideal temperature for brewing Yirgacheffe is 94°C. Over time, this method becomes your habit, until you try Yirgacheffe roasted by another roaster, and the thought "No, there's bitterness. I never have this problem when brewing other beans, it must be the beans' fault" naturally follows. (If readers think temperature is too far-fetched, replace "temperature" with technique, grind size, or ratio and read again)

This roasting style expression is even more pronounced for some lesser-known coffee origins, such as Papua New Guinea's Paradise Bird coffee beans. This bean is known as "Little Blue Mountain" because the Typica grown here came from Blue Mountain, and it's also an island-style coffee. Some roast it to medium-dark to highlight nutty, chocolatey, non-acidic flavors; others roast it to medium to show a soft, balanced sweet-sour-bitter style; while some roast it to medium-light to express white peach, plum, hawthorn, and other sweet fruit flavors.

Therefore, even for the same coffee beans, using the same brewing method (parameters) naturally won't suit different roast levels. So, understand the coffee beans first, then you can use the correct brewing method. If you're not too familiar with this aspect, you can also ask the bean's merchant for corresponding brewing parameters. Getting the right parameters means you're already halfway to success.

Main Reasons for Bitter Coffee

After getting the correct parameters, being able to use them correctly becomes key. Parameters like water temperature and ratio rarely have deviations, but the most prone to error is grind size. Many friends know what the grind size should be, but often struggle to get it right.

If the coffee grounds show large areas of mud-like consistency after brewing, either the grind is too fine or there's too much fine powder. Water can't pass through, and prolonged soaking of coffee grounds naturally leads to burnt bitterness.

FrontStreet Coffee's method for calibrating grind size is determined by the passing rate through a #20 sieve. Medium-light roast coffee uses a grind size with 75-80% passing rate. Medium-dark roast coffee uses a grind size with 70-75% passing rate.

For friends without sieves, you can also judge based on the water level's descent speed and time. According to FrontStreet Coffee's brewing parameter standards, the normal extraction time for 1-2 servings of coffee is around 1 minute 50 seconds to 2 minutes 10 seconds. If the grind is too fine, the extraction time will extend; if too coarse, the extraction time will shorten. Based on this, you can initially determine whether the coffee grind size is appropriate according to the extraction duration.

According to the water level descent speed, under normal circumstances, the coffee grounds should settle slowly and evenly. If you find the descent speed is fast, it's possible the grind is too coarse. If the settling speed becomes slower and slower, even clogging, then the grind might be too fine or there's too much fine powder, creating a muddy consistency at the bottom of the grounds.

Main Reasons for Weak-tasting Coffee

Still assuming the parameters are correct, a frequently occurring reason is that the water pour circle is too large, washing down the surrounding grounds. When the surrounding grounds wall is washed away, water will flow directly into the sharing pot along the guide ribs, without contacting the coffee grounds, so the overall taste is weak and flavorless.

So pay attention when pouring water normally - keep the pour circle smaller, and don't let the water level rise too high. Let the coffee grounds steep in water to extract the coffee flavor.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473