[Image] What to Do When Pour-Over Coffee is Too Bitter? Why Do Coffee Beans Have a Bitter and Astringent Taste?

Why Your Pour-Over Coffee Tastes Bitter and How to Fix It

Recently, some friends asked FrontStreet Coffee about their pour-over coffee often turning out bitter at home. Today, FrontStreet Coffee will explain the reasons why coffee becomes bitter and provide solutions to avoid it!

Reason 1: The coffee beans themselves have a bitter flavor profile

Coffee beans have many flavor profiles—there are fruity acidic coffees, honey and brown sugar sweet coffees, and nutty cocoa bitter coffees. If you brew Mandheling or Blue Mountain coffees, they inherently carry nutty dark chocolate flavors, so the brewed result will naturally have this type of bitterness (note: the bitterness mentioned here is different from burnt bitterness or astringency). For those who dislike bitter coffee, the nutty dark chocolate bitterness doesn't differ much from burnt bitterness or astringency.

Solution: When purchasing beans, consumers should pay more attention to the flavor description section. Although the described flavors might seem somewhat impressionistic, you can identify what flavor category this coffee belongs to, thereby choosing coffee beans that suit your taste preferences.

Reason 2: Coffee beans stored too long have lost their flavor

The optimal tasting period for roasted coffee beans is relatively short. One reason shops design packaging in 100-227 gram capacities is to consider consumption speed versus the optimal tasting period. With a daily consumption of 15 grams of coffee beans, a 227-gram package would last exactly half a month, which also aligns with coffee's optimal tasting period.

Generally, the optimal tasting period for pour-over coffee beans is 4-30 days from the roasting date. The longer they're stored, the more flavor compounds dissipate. You can confirm this by comparing fresh coffee beans with aged ones—fresh coffee beans smell very aromatic, what we often call "coffee aroma," while old coffee beans develop woody, greasy notes. Coffee beans that have lost their flavor compounds will naturally produce woody, bitter tastes when brewed.

Solution: The best solution to this problem is to drink it faster and not keep expired beans! However, FrontStreet Coffee believes the most important thing is learning to determine the optimal tasting period of beans. Checking the roasting date plus 30 days is one method, but not all coffee beans have a fixed 30-day optimal period—30 days is just a general guideline. Some beans may have longer optimal periods, while others have shorter ones. Proper storage will also extend the optimal period compared to improper storage. Therefore, to determine if it's past the optimal period, you can judge by whether the bloom expands and releases gas during blooming. If there's no reaction at all after adding water, it's likely past the optimal period.

Reason 3: Coffee ground too fine or excessive fine powder

Coffee ground too fine and excessive fine powder are two different situations, but both cause burnt bitterness during brewing. These two conditions manifest differently in terms of layering during brewing. Coffee ground too fine specifically manifests as very slow coffee bed descent from start to finish, with overall extraction time exceeding 2 minutes and 30 seconds. Excessive fine powder often manifests as normal coffee bed descent in the early stages, with progressively slower descent toward the end, sometimes even causing blockage.

Solution: The solution for grinding too fine is simple—directly adjust to a coarser setting. Pour-over grinding reference: 80% pass-through rate for #20 sieve with light roast, 70% pass-through rate for #20 sieve with dark roast.

For excessive fine powder (uneven grinding), which is caused by grinder quality issues, there are three solutions: First, upgrade to a higher quality grinder; second, use a fine powder sieve to remove the fine particles; third, during brewing, truncate the blocked coffee liquid in the final stage, then add corresponding water to return to the appropriate concentration.

Reason 4: Water temperature too high

Water temperature that's too high can also cause coffee to develop burnt bitterness. Although everyone knows this principle, they're often misled by their own experience. For example, if you frequently brew a particular bean and achieve good flavors at 93°C, over time this becomes habitual. When brewing beans with seemingly similar roast levels, you might still use 93°C, leading to unconsciously high water temperature.

For example, when brewing Blue Mountain coffee beans, with other parameters fixed, using 88°C can beautifully express the balance of Blue Mountain beans, but using 89°C would make it overly bitter and unbalanced. Yes, often just a 1°C difference!

Generally, determining if water temperature is too high is based on two conditions: First, whether you're using a reasonable temperature range—that is, 90-93°C for light to medium roasts, 86-89°C for medium to dark roasts; Second, if under the above conditions, after ruling out issues with coffee beans, roasting date, and grind size, then determine if the water temperature is too high.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473