Axit axetic trong cà phê

Acetic acid, also commonly known as vinegar, is one of many female organic acids that play an important role in the quality of pure coffee. Although there is a change in coffee, wet processed coffee and dry processing. Acetic acid formed during post-harvest processing mainly comes from fermentation.

During wet processing, microorganisms in the mucus layer use sugar to make acetic acid as well as other compounds.

Because this reaction depends on time and temperature, the concentration of acetic acid depends on environmental factors and the nature of the coffee beans when processed.

It is estimated that, after fermentation, only a very small portion of acetic acid (0.1db) produced during fermentation is retained in the coffee beans.

Coffee in the fermentation tank

However, during the roasting process acetic acid increases significantly, during roasting the carbohydrate chains such as sucrose are broken, leading to the formation of aliphatic acids such as acetic, formic and others.

Depending on the roasting conditions, acetic acid concentration can increase by 25 times compared to green coffee. The acetic acid concentration reaches its maximum concentration at the level of Light Roasts to the level of Medium Roasts. If the roasting process continues to progress, acetic acid will quickly dissolve due to the volatility of this acid.

Acetic acid concentration in green and roasted coffee

Chemically, acetic acid is volatile but plays an important role in the perception of sourness and the formation of aromas. According to Sivetz, acid accretion can be achieved by using a pressure roaster, which is said to retain volatile acids and improve the quality of roasted coffee.

Acetic acid concentration at low concentrations produces a sweet and sour character, but will quickly resemble fermentation at higher concentrations

(Original General Expert)