How do you get the aroma of coffee beans? How do we perceive the aroma of coffee? Those compounds produce aromas.

What produces the aroma of coffee? Understand chemistry

We drink coffee to enjoy its unique flavor and rich aroma. When we pour or sip espresso, it is reminiscent of chocolate, caramel, almonds, fruits and flowers. But what happened at the chemical level?

Each sensory characteristic is the result of chemical and biological reactions. Please read on to learn more about the causes of coffee aroma.

Where does the aroma of coffee come from

Green coffee beans don't smell much. Only through baking can we produce a variety of volatile compounds, resulting in a unique aroma of coffee. The taste we perceive is usually actually aroma-the tongue can only perceive taste and sweetness, saltiness, bitterness and sour taste. When these are combined with the aroma sensed by the receptors in the nose, we get the smell.

But the complexity of the aroma depends on the composition of the compounds in green beans. The precursors of these volatile compounds have different concentrations, depending on many variables, including variety, weather conditions of origin, maturity and processing options.

Which compound produces what kind of aroma?

Aroma precursors are various forms of carbohydrates, proteins and acids. During the whole roasting process, especially during the Maillard reaction, they will be converted into volatile compounds. Different compounds produce different sensory characteristics in the baking process, and the degree of baking will further affect our perception of aroma.

2-methylpyridine is responsible for roasting incense.

Pyrazine can produce nutty flavors, such as 2je 3-dimethylpyrazine, or burnt flavors, such as 2-ethyl-3-methylpyrazine.

The more advanced stage of baking leads to the caramelization of sugar. This produces furans and furanones, such as 4-hydroxy-2pyrone, 5-dimethyl-3 (2H)-furanone, which smells like caramel.

In the process of Strecker degradation, the decomposition of amino acids in aldehydes will also produce volatile compounds that produce aroma. 3-methylbutyraldehyde produces fruity and sweetness.

Ketones are also very aromatic and are the result of automatic oxidation of fatty acids such as acetone. Ketones usually provide fruity or musty flavors (β-Damasone is a ketone with the smell of fruit tea), while butter flavor is produced by smaller ketones (such as 2mae 3-butanedione).

Unpleasant aromas can also be produced during the baking process. Phenols, such as guaiacol, are produced by the decomposition of free phenolic acids during a long period of baking. They smell of ash and smoke.

How do we perceive the aroma of coffee

We now know how some volatile compounds are formed during coffee roasting. But it is also important to mention that aromas are perceived differently.

It is estimated that more than 900 aromatic volatile compounds are produced during baking, but only about 30 of them are effectively involved in the aroma and flavor we perceive in the cup. We can't detect most compounds at all. These compounds also need to be balanced so that we can have a specific sensory experience.

When we smell coffee grounds, these molecules freely interact with our olfactory receptors. When coffee powder is added to water to make a cup of coffee, other molecules are extracted, and we have different sensory experiences.