Why Does Coffee Taste Sour? Is Sour Coffee Good to Drink?

Understanding Coffee Acidity: A Beginner's Guide to Coffee Flavor

The issue of coffee flavors troubles many beginners. With so many flavors listed on flavor charts, why can't I taste them?

Why Does Coffee Have Acidity?

The term "flavor" is more commonly used in daily life as "taste," which corresponds to "flavor" in English. In coffee tasting, we typically use "notes" to describe it. In coffee, we use terms like "floral notes," "fruity notes," and "caramel notes" to describe flavors.

When a cup of acidic single-origin coffee is placed before you, can you truly discern its quality? What do we taste? What do we perceive?

Many coffee beginners only taste coffee flavor, which is completely normal. "I only taste coffee flavor, and I only smell coffee aroma!"

This is the "coffee flavor chart" in the eyes of coffee beginners, perhaps also the most intuitive perception.

For example, we might say that African beans have "bright acidity" or "fruity acidity." Wonderful acidity gives coffee richer depth and character.

Quality of Acidity

Poor Quality: Fermented sourness, harsh acidity, very high acidity, mouth-puckering, vinegar-like acidity

High Quality: Fruity acidity, fresh acidity, rounded acidity, soft acidity

High-quality coffee often contains large amounts of organic acids, embodying rich acidic flavors like citrus and berries. The quality of acidity is an important factor in specialty coffee.

For example, FrontStreet Coffee's series of coffee beans includes the following types of acidity:

Sidamo: Wild ginger, bergamot, blackcurrant, various tropical fruit acids

Flower Butterfly (70% Geisha content): Tea aroma, honey, typical Esmeralda Geisha Estate flavor

Natural Red Label: Berry, floral, grape acidity, peach

Learning to Appreciate Coffee Acidity

Many people dislike acidity in coffee, preferring very mellow or even strong-flavored coffee. But if you want to become a coffee connoisseur, the key to getting started is understanding acidity in coffee. It must be noted that more acidic coffee is not necessarily better. The sweet and acidic substances in coffee are components that contribute to the complexity of coffee flavor. Some coffees have very high acidity that is mouth-puckering and can only receive low scores in professional cupping. Other coffees may have acidity, but it's a comfortable, rounded acidity that balances with sweetness, earning higher scores.

The Source of Coffee Acidity

Green coffee beans contain components related to acidity such as citric acid, malic acid, quinic acid, and phosphoric acid, but these are not the sources of acidity we perceive when drinking coffee. The acidity created during roasting is the main source of acidic flavor.

Once green beans are roasted, various components undergo chemical reactions, creating new acids. The most representative reactions include the decomposition of chlorogenic acids to produce quinic acid, and the breakdown of oligosaccharides to produce volatile formic acid and acetic acid.

If a cup of coffee has only bitterness or acidity without other flavors, then it's a very poor cup. There's an essential difference between acidity and astringency. Acidity is perceived when you feel saliva production on both sides of the back-middle portion of your tongue after drinking coffee, while astringency is a spicy and rough sensation on the tongue surface, throat, and palate after drinking, like drinking coffee with gauze strips.

Astringency is an undesirable taste in coffee, representing defects from green beans to roasting and even brewing. A good cup of coffee should not be bitter or astringent.

Techniques for Distinguishing Coffee Flavor and Aroma

"The dry aroma of this bean leans toward the elegant jasmine, with pleasant, lively acidity, sweet-acid balance, and acidity transitioning to sweetness."

Blue Label Geisha with sweetness is like a fruit, containing fructose in the coffee beans, sweet potato sweetness similar to sucrose, brown sugar, caramel, with a mouth-watering sensation.

"The aftertaste is excellent! First, there's a hint of passion fruit acidity, then a full aftertaste, and finally some nutty notes in the finish."

"I still prefer the taste of Geisha when it cools down - the sweetness is more pronounced, with peach flavors and sweet potato sweetness."

Just like wine tasting, besides aroma, you can pay extra attention to the coffee's "body" - is it full and heavy or light? Is it watery thin or thick like syrup? Is the acidity dull, lively, or strong? Finally, you can consider the coffee's aftertaste and overall complexity.

Learning to appreciate coffee is a long process. Beginners shouldn't be discouraged by temporary difficulties. Expose yourself to more coffee, taste more varieties, and appreciate coffee using the three steps of smelling aroma, tasting flavor, and savoring aftertaste. Slowly, you'll discover the wonderful world of coffee flavors.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473