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The cup of coffee you are using every day contains acid!


When drinking specialty coffee, you can feel like you are biting into a fresh lemon slice or grapefruit segment with a clean, crisp feeling. That feeling is caused by the acid in coffee. With countless individual acids and compounds reacting together, your cup of coffee will have richer acidity. The senses are stimulated to create refreshment and novelty of the characteristics of each type. Join 43 Factory Coffee Roaster to find out the acids in your cup of coffee!


Acid in coffee contributes to the sharpness of the flavor


From a sensory perspective during the cupping process, acid has a profound impact on the quality of a cup of coffee. It is recognized as a fundamental element of flavor to more fully evaluate the standards of flavor characteristics. In coffee, acid accounts for about 11% of the overall volume for green beans and  6% for roasted beans, helping the flavor when extracted have a certain cleanness, clarity, and sourness. Furthermore, depending on the content and type of acid in the beans, coffee can evoke unique flavors.

You can enjoy a cup of coffee and feel like you are biting into an apple. Or the taste of coffee reminds you of the fruity, juicy, bright, refreshing flavor of lemon, apricot or grapefruit. These are all inherent sensory characteristics of each type of acid. Citric, acetic, malic, quinic, pyruvic, succinic, fumaric, and tartaric acids are acids that tend to create sour tastes (of lemons, apples,…). Some acids have a characteristic aroma such as vinegar smell from acetic acid, burnt caramel flavor from pyruvic acid, or pungent aroma and fermentation in formic acid. In addition, acids that can create a bitter taste in coffee include formic, quinic, succinic, and caffeine. Organic acids such as quinic and lactic acid contribute to the mouthfeel and chemical sensation of astringency. Organic acids such as fumaric, tartaric, and oxalic can help coffee increase its aroma and flavor, giving a cup of coffee more depth and richer acidity.

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A cup of coffee doesn’t have just one type of acid


Acids in coffee are often divided into two types: organic acids (OA) and chlorogenic acids (CGA). Each type will have characteristics that create special scents and acidity.


Organic acids


According to research by the Department of Food Science & Technology, University of California, roasted coffee contains up to thirty-eight organic acids. The most common and often highest concentrations are citric, malic and quinic acids. Roasted coffee usually has greater overall acidity than green coffee. This is due to the increase in formic, acetic, glycolic and lactic acids formed during roasting. In particular, Sucrose acts as the main precursor of these acids. This means that differences in the amount of sucrose in the final green coffee will contribute to different amounts of final acid. Furthermore, citric and malic acids, inherent in green coffee beans, can act as precursors to other acid breakdown products, such as citraconic, glutaric, fumaric and maleic acids.

Increasing any amount of acid will decrease the pH and increase the titratable acidity of the final product. For example, in small amounts, acetic acid will evoke winey acidity. But if there is too much acetic acid, the coffee will taste bitter and vinegary (vinegary bitterness). Coffee containing a lot of Malic acid will have a sour apple taste, while coffee containing a lot of citric acid will taste like lemon or orange.


Chlorogenic acid


Chlorogenic acids (CGA) are naturally occurring bioactive compounds that accumulate in beans as coffee cherries mature. CGA includes many different quinic acid esters. During roasting, CGA decomposes slowly, forming caffein and quinic acids. These subgroups include caffeoylquinic acid (CQA), dicaffeyloquinic acid (diCQA) and feruloylquinic acid (FQA). This is the acid that creates the bitter taste of coffee and also contributes a small part to the stimulating effect of coffee.

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If you love and want to experience specialty coffees with rich acidity, visit XLIII Coffee – The brand developed from the predecessor 43 Factory Coffee Roaster.

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