Why Does Coffee Have Sour Notes? How to Understand Acidity in Coffee

Understanding Coffee Acidity: A Beginner's Guide to Tasting

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

It's quite normal for many coffee beginners to only taste "coffee flavor" in their coffee. I'm just tasting coffee, and smelling only coffee aroma!

This is what the "coffee flavor wheel" looks like through the eyes of a coffee novice - perhaps 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 complexity.

Types of Coffee Acidity

Poor Quality: Rotten sourness, sharp acidity, very high acidity, mouth-puckering, vinegar-like sour

High Quality: Fruity acid, fresh acidity, rounded acidity, smooth acidity

High-quality coffee often contains abundant organic acidic compounds, embodying rich acidic flavors like citrus and berries. The quality of acidity is a crucial factor in specialty coffee.

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

• Sidamo: Wild ginger, bergamot, blackcurrant, and various tropical fruit acids
• Flower Butterfly (70% Geisha content): Tea aroma, honey, classic Emerald Manor Geisha flavor
• Natural Red Label: Berries, floral notes, grape acidity, peach

Learning to Appreciate Coffee Acidity

Begin to accept acidity in coffee, distinguish between various types of acidity, and experience the acidity levels.

Many people dislike acidity in coffee, preferring very full-bodied or even strong-flavored coffee. However, if you want to become a coffee connoisseur, the key to getting started is understanding acidity in coffee. It must be noted that the more acidic a coffee is, the better it is. The sweet and acidic substances in coffee are components that contribute to the complexity of coffee flavor. Some coffees have very high acidity that makes the mouth pucker, receiving very low scores in professional cupping. Other coffees, though acidic, have a comfortable and rounded acidity that balances with sweetness, thus receiving higher scores.

The Science Behind Coffee Acidity

Green coffee beans contain citric acid, malic acid, quinic acid, phosphoric acid, and other acidity-related components. However, these are not the source of the acidity we perceive when drinking coffee. The acidity created during roasting is the main source of acidic flavors.

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

Distinguishing Acidity from Astringency

If a cup of coffee has only bitterness or acidity with no other flavors, then it's a very poor cup. There's an essential difference between acidity and astringency. Acidity is perceived when the sides of the back and lower part of the tongue start to salivate after drinking coffee, while astringency is a spicy, rough sensation on the tongue surface, throat, and palate after drinking, like the feeling of 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.

Coffee Tasting Techniques

When we taste coffee, we need techniques to distinguish between flavor and aroma.

"The dry aroma of this bean leans toward the elegant jasmine flower, with pleasant and 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, with sweet potato sweetness, similar to sucrose, brown sugar, caramel, creating a mouth-watering sensation.

"This aftertaste is wonderful! First, there's a bit of passion fruit acidity, then a full aftertaste, and finally the finish has some nutty notes."

"I still prefer the taste of Geisha as 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" - whether it's full and heavy or light, as thin as water or as thick as syrup. Is the coffee's acidity dull, lively, or strong? Finally, you can consider the coffee's aftertaste and overall complexity.

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

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473