Coffee review

Coffee roasting should master the yardstick

Published: 2024-11-15 Author: World Gafei
Last Updated: 2024/11/15, Basically, the roasting of coffee is a kind of high temperature coking (Pyrolysis), which completely changes the substance inside the raw bean, produces new compounds, and recombines to form aroma and mellow flavor. This effect will only occur at high temperatures. If only low temperatures are used, it will not cause decomposition, no matter how long the coffee beans are not cooked.

There are many drinks all over the world: tea, wine, leaf palmatine, cocoa, coffee, etc., but coffee has become the first drink, due to the reason: in the roasted coffee contains 700~800 kinds of substances related to flavor. Arabica beans contain more than 2000 ingredients, wine has more than 500 flavor-related substances, and vanilla has 150.

Definition of baking

Basically, coffee roasting is a pyrolysis that completely changes the substances inside the green beans, producing new compounds and recombining them to form aromas and alcohol flavors. This effect only occurs at high temperatures, and if only low temperatures are used, decomposition cannot be caused, no matter how long the coffee beans are roasted.

In this process, coffee will undergo considerable changes, mainly in the following aspects:

★ Weight loss: After roasting, the water evaporates and the moisture content of the coffee beans drops from 13% to 1%. Moreover, the silver skin falls off and some substances volatilize at high temperatures, so coffee beans will lose weight by 12% to 21%. The deeper the roasting, the greater the weight loss.

Volume expansion: At the end of this process, the volume of coffee beans will increase by 60%.

★ Cell pore enlargement: The cell wall of raw beans is hard and the cell pores are closed, so it is not easy to deteriorate. But after baking, the cell walls become fragile, and the larger the pores, the easier it is to lose material.

★ Carbon dioxide formation: Carbohydrates inside coffee beans decompose during high temperature decomposition, and combine with other substances to form a large amount of carbon dioxide, which resides inside coffee beans.

Changes in organization and structure: Roasting changes the internal organization of coffee. Carbohydrates decreased from 58.9% to 38.3%.

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