Are Bitter Coffee Beans Inferior? Understanding Coffee Bitterness and How to Choose Non-Bitter Beans

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Is Bitterness Always Bad?

Bitterness has always been an unpopular term in specialty coffee. Good coffee should be fragrant, sweet, and have excellent balance - perhaps with some acidity, and should taste delicious without adding sugar. But what exactly makes coffee bitter? Is this bitterness really that bad? Let's explore.

Actually, bitterness isn't that bad. In fact, if there were completely non-bitter coffee beans, they might taste too sour or too sweet. The key here is "balance." A little bitterness can bring out richer and more diverse flavor layers, provided the bitterness isn't overpowering.

However, interestingly, for most people, we can accept very bitter coffee more than very sour coffee.

Nevertheless, coffee that's too bitter is indeed terrible, so let's examine what bitterness really is and how to avoid it during brewing.

What is Bitterness?

Everyone has experienced bitterness, but often there are situations where you taste bitterness while others don't. This is sensory perception of taste, representing how sensory experiences vary from person to person.

Equally important to note is that taste isn't just about creating the sensation of bitterness. The word "flavor" represents the combination of many things, including smell, emotions, music, and even altitude can have an influence. However, this isn't what we're exploring in this article. For now, let's focus on taste and examine coffee bitterness from a scientific perspective.

The Science of Bitterness

People used to think that different taste sensations were distributed across the tongue, with sweet, salty, sour, and bitter each having different reception areas. But now we know that all these flavors can be perceived in any region of the tongue.

Because our tongue's sensory cells contain many proteins, according to the American Institute for Medical Quality and Efficiency, about 35 proteins react with compounds in food to create the sensation of bitterness.

This means bitterness comes from substances in coffee called phenolic compounds, the most common of which are called chlorogenic acids, which we'll discuss later. In raw Arabica coffee beans, these substances account for about 8%, and they have a significant impact on the taste experience when drinking coffee.

There are many types of chlorogenic acids, but we only need to understand the two most distinctive ones: chlorogenic acid, the most common compound in raw beans, and di-CGA, which is the main substance that reflects coffee bitterness.

Although most coffee bitterness comes from quinic acid, research indicates that caffeine also affects bitterness, but caffeine's influence on bitterness is at most secondary.

Bitterness from Raw Beans

When we talk about coffee bitterness, we often think of roasting, but in fact, some coffees contain more bitterness than others.

First, Robusta coffee is more bitter than Arabica because Robusta has higher chlorogenic acid and caffeine content. Robusta's chlorogenic acid content reaches 10% in its raw state, while Arabica has only 2%. Additionally, Robusta's caffeine content is nearly twice that of Arabica.

However, it's not just coffee variety that affects bitterness. In 2006, the Brazilian Journal of Plant Physiology published research on phenolic compounds: "Variety, species genetics, maturity, external environmental factors, and growing conditions are all important factors affecting quinic acid content in raw beans, which in turn affects the final cup of coffee you drink."

The research also mentioned the impact of processing methods, particularly the monsoon processing method. This is a traditional Indian processing method that exposes raw beans to high-humidity monsoon environments. This processing method can reduce the chlorogenic acid and bitterness in raw beans.

As for coffee cherry maturity, research pointed out: "For example, unripe beans contain more quinic acid, which is why a cup of coffee with many unripe beans will be very bitter and astringent."

Does Roasting Increase Coffee Bitterness?

During roasting, chlorogenic acids change and break down. Although the main bitterness in coffee comes from chlorogenic acids, in fact, chlorogenic acids themselves are not bitter! During roasting, chlorogenic acids break down into "chlorogenic acid lactones" and "phenylindanes." In 2007, pioneering scholar Thomas Hofmann pointed out that phenylindanes produce partial bitterness, and they also affect the flavor of coffee roasting.

Light to medium roasted coffees will have more chlorogenic acid lactones. Hofmann described this roast level as "pleasant, quality coffee bitterness." Darker roasted coffees have more phenylindanes, with "strong bitterness that lingers in the mouth."

So light to medium roasted coffees will have lower bitterness and retain the original aroma and flavor of the coffee. But of course, bitterness is a subjective experience - just because you don't like bitterness doesn't mean others don't like it.

How to Avoid Bitterness During Brewing

If you buy light-roasted, high-quality Arabica, can you avoid bitterness? Not necessarily. Whether you brew it yourself or a professional barista brews it, it will still affect the final flavor in the cup.

Avoid over-extracting coffee to prevent bitterness, because bitterness is largely released during the later stages of brewing. There are many variables in extraction: brewing method, grind size, water temperature, brewing time, etc. Here are some suggestions.

First, regardless of what brewing method you use, ensure proper coffee grind size. The finer the grind, the greater the surface area of coffee contact, and while it will extract more concentrated coffee, it also increases the risk of over-extraction.

Next, check your water temperature. The higher the water temperature, the more substances are extracted. If the coffee beans have stronger bitterness, it's recommended to brew with lower water temperature.

Then look at brewing time. If the coffee is more bitter, it might mean the brewing time is too long.

Finally, remember that extraction is about achieving overall balance. If you adjust brewing variables, such as grind size, then brewing time will also be affected.

A delicious cup of coffee requires the right combination of grind size, water temperature, and brewing time. Source: Matt Fury

Bitterness isn't always that bad, but it becomes problematic when it overpowers other flavors. However, after reading this article and understanding the sources of coffee bitterness, we can explore how to control these variables.

Follow the recommended steps to find the balance and flavors you like in coffee.

Recommended Low-Bitterness Coffee Bean Brands

Low-bitterness coffee beans roasted by FrontStreet Coffee: washed Yirgacheffe coffee, Kenya AA coffee, Panama Geisha coffee, etc., all have full guarantees in terms of brand and quality. More importantly, they offer extremely high value for money. A half-pound (227 grams) package costs only around 80-90 yuan. Calculating at 15 grams per pour-over coffee, one package can make 15 cups of coffee, with each single-origin coffee costing only about 6 yuan. Compared to café prices that often charge dozens of yuan per cup, this offers exceptional value.

FrontStreet Coffee: A roastery in Guangzhou with a small shop but diverse bean varieties, where you can find various famous and lesser-known beans, while also providing online shop services. https://shop104210103.taobao.com

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473