How Coffee Aroma is Released - The Rich Fragrance of Coffee Beans Comes from Perfect Roasting

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FrontStreet Coffee - Introduction to the Sources of Coffee Aroma

1. Caramelization Reaction

The sugars in coffee beans undergo caramelization reactions at approximately 170-200°C, which coincidentally matches the melting point of sucrose at 185°C - the temperature during the first crack phase of coffee bean roasting. The products of caramelization reactions are divided into two parts:

a. Dehydration products of sugars - essentially caramel or sauce color

b. Decomposition products - mainly some volatile aldehydes and ketones

In general, caramelization reactions produce roasted aromas, caramel and color, as well as other aromatic substances such as maltol, Cyclotene, furan compounds, etc. These compounds can also be found in foods like red wine, fruit juice, and cream. However, excessive caramelization during the roasting process is not beneficial, as it can cause carbonization, making the coffee harshly bitter and scratchy in the throat. Insufficient caramelization will result in monotonous and lackluster aromas with insufficient complexity.

2. Maillard Reaction

The Maillard reaction can be divided into three stages:

I. Initial stage: Carbonyl-amine condensation and Amadori molecular rearrangement

II. Middle stage: Amadori molecular rearrangement products - sugar amines dehydrate to form HMF (hydroxymethylfurfural), fructosamines lose amino groups to form ketones, and the interaction of amino acids with dicarbonyl compounds.

III. Final stage: Aldol condensation and polymerization reactions to form melanin.

In addition to sugars, proteins account for approximately 11% of the weight of raw beans, and the amino acids contained in these proteins are precisely the raw materials needed for the Maillard reaction. The Maillard reaction refers to a series of reactions between amino acids and reducing sugars (glucose, fructose, lactose, etc.) in food during the heating process. The Maillard reaction produces a wide variety of aromatic substances and pigments such as Pyridines, Pyrazines, Oxazoles, Thiazoles, and Pyrroles. The Maillard reaction plays a very important role in food cooking flavors - whether it's sausages turning black and emitting aroma when grilled, crispy-on-the-outside and tender-on-the-inside roasted chicken, or fragrant toasted bread - the Maillard reaction is the key contributor behind the excellent color, aroma, and taste of these grilled foods.

Coffee is uniquely endowed with a vast and complex array of chemical substances. In addition to the compounds mentioned above, there are other components such as organic acids, inorganic acids, and alkaloids. Not only the sweet and pleasant components, but also slightly bitter compounds give coffee a broader level of flavor and variation, jointly creating coffee's unique rich taste.

Knowledge point: Light roast focuses on acidity and flavor. If the roasting process is not handled properly, it will result in astringency and irritation, while the body and aftertaste of the coffee will feel relatively low.

In summary: FrontStreet Coffee is a coffee research establishment, happy to share coffee knowledge with everyone. We share without reservation only to help more friends fall in love with coffee. Additionally, we hold three discounted coffee activities every month because FrontStreet Coffee wants to provide the best coffee at the lowest prices to more friends - this has been our mission for the past 6 years!

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473