Chemistry of Coffee
Elisa Hofmeister
Kokesh Hour 3
AP Chemistry
5-29-12
The Chemistry of Coffee
Green Coffee-
Before coffee is roasted, it is referred to as “green coffee”. The green coffee is primarily made up of caffeine, lipids, carbohydrates, proteins (amino acids), and organic acids (although inorganic acids exist in coffee as well). These groups are quite stable in the green phase, and it is the carbohydrates, proteins, and acids that will undergo significant reactions during roasting to produce coffee. The important groups of carbohydrates in beans are from the monosaccharides and the polysaccharides found in beans. The disaccharide Sucrose (C12H22O11) also plays a vital role later on in coffee. Generally speaking, Monosaccharides represent the simplest forms of sugars, such as glucose and fructose, and usually follow the formula Cx(H2O)y. These sugars serve as building blocks for polysaccharides like starches and cellulose, which are usually long repeating chains of a basic unit or monosaccharide. All together, carbohydrates represent about 50% of green coffee’s base. Amino acids are present in green coffee at levels of about 10-13% of dry matter. Amino acids are molecules containing an amine, a carboxylic acid group (an organic acid that contains at least one carboxyl group of COOH) , and a side chain (a chemical grouping that is attached to the main group and is specific to each compound). Lipids represent around 11-17% of coffee. They do not play a huge role in the chemical processes of creating coffee- rather, they act as conductors of aroma and taste later on in the coffee process. Caffeine, an astringent stimulant, develops in coffee as a defense mechanism in the coffee plant. Its content remains stable throughout roasting and brewing. It is highly water soluble. Finally, green coffee beans contain numerous acids. Chlorogenic , Citric, Phosphoric, and Quinic Acids represent some of the most important acids in the green coffee bean. A small amount of acetic acid
Kokesh Hour 3
AP Chemistry
5-29-12
The Chemistry of Coffee
Green Coffee-
Before coffee is roasted, it is referred to as “green coffee”. The green coffee is primarily made up of caffeine, lipids, carbohydrates, proteins (amino acids), and organic acids (although inorganic acids exist in coffee as well). These groups are quite stable in the green phase, and it is the carbohydrates, proteins, and acids that will undergo significant reactions during roasting to produce coffee. The important groups of carbohydrates in beans are from the monosaccharides and the polysaccharides found in beans. The disaccharide Sucrose (C12H22O11) also plays a vital role later on in coffee. Generally speaking, Monosaccharides represent the simplest forms of sugars, such as glucose and fructose, and usually follow the formula Cx(H2O)y. These sugars serve as building blocks for polysaccharides like starches and cellulose, which are usually long repeating chains of a basic unit or monosaccharide. All together, carbohydrates represent about 50% of green coffee’s base. Amino acids are present in green coffee at levels of about 10-13% of dry matter. Amino acids are molecules containing an amine, a carboxylic acid group (an organic acid that contains at least one carboxyl group of COOH) , and a side chain (a chemical grouping that is attached to the main group and is specific to each compound). Lipids represent around 11-17% of coffee. They do not play a huge role in the chemical processes of creating coffee- rather, they act as conductors of aroma and taste later on in the coffee process. Caffeine, an astringent stimulant, develops in coffee as a defense mechanism in the coffee plant. Its content remains stable throughout roasting and brewing. It is highly water soluble. Finally, green coffee beans contain numerous acids. Chlorogenic , Citric, Phosphoric, and Quinic Acids represent some of the most important acids in the green coffee bean. A small amount of acetic acid