Coffee contains several sulphuric compounds that contribute to its signature aroma and taste due to their low odor thresholds. The different amino acids in coffee beans also contain sulfur.
Trace levels of specific sulfur-containing compounds often are responsible for imparting the characteristic pleasant taste and aroma of coffee, while increased concentrations or absence of selected compounds may be responsible for variations in flavor among different blends.
Sulfur compounds are usually not present in green coffee, with the exception of dimethylsulfide. Different roasting and processing methods can induce different reactions in the sulfur content, producing different tastes, odors, and aromas.
When coffee beans are roasted, amino acids and sugars combine and begin a profusion of reactions that ultimately create the smell, taste, and color of the coffee. This is called the Maillard Reaction and is responsible for turning a few dozen compounds inside the coffee bean into hundreds, even thousands of aromatic compounds that make up the unique flavors of coffee.
Several sulfur-containing compounds are of importance, including 2-furfurylthiol, with an aroma that on its own is actually commonly described as ‘roasted coffee’.
Another sulfur-containing compound, 3-mercapto-3-methylbutyl formate, is brilliantly described as having a ‘catty’ odour in isolation.
Sulfur compounds in coffee
