Is coffee a base?

In this article, we will answer the question “is coffee a base?”. In addition, we will discuss the reasons why coffee is acidic, what are the components present in coffee and what is the relationship between the pH of coffee and caffeine.

Is coffee a base?

No, coffee isn’t a base. The ideal pH of coffee ranges from 4.95 to 5.20. In other words, the coffee is acidic. However, caffeine, one of the main compounds present in coffee, is basic.

Let’s see details about this.

Why is coffee acidic?

The acidity of coffee is related to the presence of carboxylic acids and chlorogenic acids.

Acidity is a very important flavor attribute. Generally, high-quality coffee has pronounced acidity, being classified as bright or tangy. In this type of coffee, the beans are submitted to severe roasting conditions and produce coffee with lower acidity because of chlorogenic acid degradation.

Acidity is also correlated with pH. Coffee with superior quality has higher titratable acidity than coffee with inferior quality. Consumer acceptance is highly associated with coffee beverage pH.

What interferes with coffee acidity?

The intensity of coffee acidity is related to factors such as fermentation levels, weather conditions during harvesting and drying, maturation stages, place of origin and preparation method. The fermentation of coffee beans contributed to increasing acidity because during its process the production of alcohols and acids occurs, through various biochemical routes.

The acidity of fruits tends to decrease with ripening, due to the use of organic acids in breathing or their conversion to sugars.

What acidic compounds are present in coffee?

The types of acids found in coffee brews are aliphatic carboxylic acids and some carbocyclic acids. Carboxylic acids are those that have a carboxyl group (COOH) in their composition. The presence of inorganic acids such as phosphoric acid is also reported. 

The acidic fraction of coffee has non-volatile acids such as oxalic, malic, citric, tartaric and pyruvic and volatile acids such as acetic, propionic, valeric and butyric. According to the present concentration of these acids, it can impart a pleasant or unpleasant odor and taste to the drink. 

Although it is not yet clear which compounds are responsible for the perceived acidity, it is known that citric, malic, acetic, quinic and chlorogenic acids are the acids in the greatest quantity in coffee beans, and may be responsible for sensory acidity. Citric and malic acids are the most widely and abundantly occurring acids in vegetables. 

Another acid of great importance in coffee is chlorogenic acids. They are a set of five main groups of phenolic compounds and their isomers formed primarily by the esterification of quinic acid with one of the following acids: caffeic acid, ferulic acid or p-coumaric acid. 

During roasting, coffee may have lower acidity due to the destruction of chlorogenic acids that are linked to the bean matrix. Chlorogenic acid is degraded releasing caffeic acid, quinic acid and others. 

In this way, chlorogenic acids decrease in roasted coffee, and the less roasted the coffee, the greater the acidity. Caffeic and quinic acids are partially hydrolyzed, isomerized or degraded to low molecular weight compounds that contribute to flavor and aroma. 

It is evident that the quinic acid content continually increases, as the chlorogenic acid decreases during roasting. Robusta coffee (3.9 – 4.6%) contains more chlorogenic acids than Arabica coffee (1.2 – 2.3%).

Chlorogenic acids, as phenolic compounds, play an important role in human health. Foods with significant amounts of chlorogenic acids are highly targeted as they have several proven biological functions. 

Studies reveal that they have several pharmacological properties, such as the ability to increase hepatic glucose utilization, antioxidant activity, antispasmodic activity, inhibition of HIV-1 integrase, and inhibition of mutagenicity of carcinogenic compounds.

Carboxylic acids are present in greater amounts than chlorogenic acids in green coffee. The main ones found in coffee are citrus, malic, oxalic and tartaric. The acidity perceived in the coffee drink has always been recognized as an important quality attribute. 

Citric and malic acids are related to the desired acidity of coffee, and Arabica coffee has higher concentrations of these acids. Improper or undesirable acidity can result from excessive fermentation of the fruit. In this way, raw coffee stored for a long period is slightly more acidic than freshly picked beans.

Why is caffeine basic?

Caffeine is an organic compound in the alkaloid family. Alkaloids, in turn, are cyclic amines that have nitrogen-containing heterocyclic rings. 

Alkaloids are so called because they have basic or alkaline properties (their name means “similar to alkalis”), so caffeine is also basic.

In addition to being an alkaloid, caffeine is an amide (a substance that has nitrogen attached to a carbonyl group).

Conclusion

In this article, we answered the question “is coffee a base?”. In addition, we discussed the reasons why coffee is acidic, what are the components present in coffee and what is the relationship between the pH of coffee and caffeine.

Citations

https://www.taylorlane.com/blogs/read/is-coffee-an-acid-or-a-base.
https://fullcoffeeroast.com/is-coffee-an-acid-or-a-base/

Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.