Understanding and identifying Astringency in coffee

What is Astringency in coffee?
Astringency, also known as an astringent taste, is a common sensory phenomenon when enjoying coffee. It’s not a flavor but a dry, rough feeling in the mouth, similar to eating an unripe persimmon. This sensation is caused by polyphenols, particularly tannins. These compounds bind with proteins in saliva, causing tissues in the mouth to contract, leading to an uncomfortable dry and rough sensation.

Why is Astringency important in coffee?
Astringency is a crucial element to recognize when tasting coffee, especially in Specialty coffee. It can significantly diminish the richness of the flavor and negatively impact the overall tasting experience. Understanding and managing this sensation helps coffee drinkers fully appreciate the subtle notes that a high-quality cup of coffee offers.

Polyphenols and tannins in coffee
Polyphenols, especially tannins, are natural compounds found in coffee. These complex molecules can bind with proteins and other compounds in the mouth, leading to the astringent sensation. Tannins, in particular, can precipitate proteins in saliva, reducing its viscosity and causing dry mouth. Tannins also affect bitterness and other flavors in coffee. Coffees with high tannin content, such as those that are over-extracted, tend to have a stronger astringent effect.

Growing and processing conditions
The growing conditions and processing methods also play a significant role in determining the tannin content and astringency in coffee. Research suggests that coffee grown in high-altitude regions often has higher polyphenol content due to harsher growing conditions, such as stronger sunlight and lower temperatures.

Natural processing methods tend to retain more tannins, particularly when coffee beans are dried with their outer skin intact. During this process, polyphenols from the fruit’s skin can seep into the coffee beans, creating a more pronounced astringent sensation.

In contrast, washed processing methods often remove the outer skin and mucilage earlier, reducing the absorption of polyphenols into the beans, thus lowering the astringency in the final product.

Brewing and extraction process
The brewing process can also increase astringency. Over-extraction of coffee can release more polyphenols, leading to a stronger astringent sensation. Controlling water temperature and brewing time is essential to avoid enhancing this sensation.

Polyphenols, particularly tannins, are natural compounds in coffee beans that can bind with proteins and other compounds in the mouth, leading to the sensation of astringency in coffee

How to identify Astringency by taste
Astringency is most noticeably felt on the tongue and the inner cheeks. It’s a dry, rough, and slightly coarse sensation, similar to eating an unripe persimmon or drinking over-brewed black tea. When you experience this sensation, you’ll notice your mouth becoming drier, and the flavor of the coffee may diminish significantly, making it difficult to detect other flavor notes.

Distinguishing Astringency from other tastes
Astringency is often confused with bitterness, but they are not the same. Bitterness is a specific taste, while astringency is a physical sensation. While bitterness can accompany astringency, not all astringency is bitter. To distinguish, focus on how the coffee makes your mouth feel dry and rough, rather than just the taste.

Bitterness and astringency can also be mistaken for each other, especially when they occur together in a cup of coffee. Bitterness is one of the five basic tastes that the tongue can detect, caused by compounds like caffeine, quinine, and some polyphenols. A good way to differentiate is by noticing the timing. Bitterness usually hits immediately upon taking a sip, while astringency may develop more slowly, as your mouth begins to feel dry and slightly raw. Additionally, bitterness can linger after swallowing, while astringency leaves your mouth feeling dry and parched.

Astringency is most noticeably felt on the tongue and the inner cheeks as a dry, rough, and slightly raw sensation, similar to eating an unripe persimmon or drinking over-brewed black tea

Effect on overall coffee flavor
Astringency not only dries out the mouth but also reduces the ability to perceive coffee’s full flavor. Polyphenols combined with saliva proteins create a thin film on the tongue, hindering the interaction between taste buds and the coffee’s flavor compounds. This makes it harder to detect delicate flavor notes, particularly fruity or floral ones, reducing the richness and complexity of the Specialty coffee experience.

Managing and reducing Astringency
To minimize astringency, selecting the right processing method and adjusting the brewing process is crucial. Choosing coffees processed by washed methods can reduce polyphenol content. During brewing, pay attention to extraction time and water temperature to avoid over-extraction. Using slightly lower water temperatures or reducing brewing time can help reduce astringency while preserving the coffee’s natural flavors.

To minimize astringency, selecting an appropriate processing method and adjusting the brewing process are crucial

Methods to reduce Astringency in coffee

Astringency can be minimized by carefully selecting coffee beans and adjusting the brewing method. To avoid this sensation, focus on the following points:

• Select high-quality coffee beans: Opt for beans grown at ideal altitudes and processed using washed or meticulously handled methods to limit tannin content. Coffees from highland regions like Ethiopia, Kenya, or Colombia often have rich flavors without excessive astringency.

• Adjust extraction time and temperature: Astringency increases with over-extraction. To counter this, try reducing the extraction time or using slightly cooler water, typically around 90-92°C instead of the usual 96°C. This helps limit the release of polyphenols, reducing astringency while maintaining flavor.

• Experiment with brewing methods: Some brewing methods, such as Aeropress or cold brew, can reduce astringency due to their gentler extraction processes. Experiment with these methods to find the optimal brewing approach for your coffee beans.

When is Astringency acceptable in Specialty Coffee?

In the world of Specialty coffee, a slight level of astringency can actually add complexity to the overall flavor. It can balance acidity and help differentiate various flavor notes, particularly when combined with coffee beans that have a strong flavor profile.

However, it’s essential that astringency doesn’t dominate and overshadow other characteristics of the coffee. A mild, gentle astringency may be acceptable, but if it becomes too strong, it will overpower other flavors and detract from the enjoyment of the coffee.

Is Astringency a sign of poor coffee quality?

Astringency is not necessarily a sign of poor-quality coffee. However, when it is too strong or poorly controlled, it can indicate issues in production or brewing:

• Quality of coffee beans: Strong astringency can result from using unripe or improperly processed coffee beans. Beans picked too early or processed incorrectly may contain higher polyphenol levels, leading to more pronounced astringency.

• Suboptimal processing methods: Certain processing methods, like dry processing, if not done carefully, can increase tannin content, leading to more astringency. This doesn’t mean the coffee is of poor quality, but it can affect the drinking experience.

• Over-extraction: As mentioned, over-extraction is a common cause of astringency. This can result from errors in the brewing process, but it may also indicate that the coffee was roasted too darkly or brewed with incorrect techniques.

Astringency can overshadow other characteristics of coffee if it exceeds a certain threshold

Conclusion
Astringency is an essential factor to understand when enjoying coffee. It affects not only the flavor but also the overall drinking experience. Recognizing and managing astringency helps you evaluate coffee more professionally. A perfect cup of coffee isn’t just about flavor; it’s also about the sensation and how it impacts you. By understanding and controlling this element, you can enjoy Specialty coffee more fully, exploring all the subtle and unique notes that each cup offers.

Images from XLIII Coffee and collected by XLIII Coffee

1. What is Astringency in coffee?

Astringency in coffee, also known as astringency, is the dry, rough feeling in the mouth and throat after drinking coffee. It is usually caused by polyphenol compounds like tannins binding with proteins in saliva, leading to the contraction of tissues on the tongue and creating a dry sensation.

2. How can I reduce Astringency in coffee?

To reduce astringency, choose high-quality coffee beans, adjust extraction time and temperature during brewing, and experiment with gentler brewing methods like Aeropress or cold brew to achieve a smoother extraction.

3. Is Astringency acceptable in Specialty coffee?

A mild level of astringency can be acceptable in Specialty coffee, as it may add complexity and balance to the flavor. However, it should not be overpowering, as excessive astringency can overshadow other flavor notes and diminish the overall enjoyment.

4. Is Astringency a sign of poor coffee quality?

Astringency is not necessarily a sign of poor coffee quality. It can result from several factors, such as bean quality, processing methods, or over-extraction during brewing. However, strong or poorly managed astringency can indicate potential issues.

5. Which brewing methods can reduce Astringency in coffee?

Brewing methods like Aeropress and cold brew often result in gentler extractions, which can help reduce astringency. These methods use lower pressure or cooler water, limiting the release of polyphenols and leading to a smoother mouthfeel.