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Coffee roasting physical changes of coffee roasting temperature and time during coffee roasting

Published: 2024-11-17 Author: World Gafei
Last Updated: 2024/11/17, For more information on coffee beans, please follow the coffee workshop (official Wechat account cafe_style). Roasting converts coffee beans from raw beans to ripe beans with rich aroma and flavor, but do you know what happened during the roasting process? When we bake beans, they are mainly divided into physical and chemical changes, volume and pores, and the cell wall strength of coffee beans ranks at the top of the plant kingdom.

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Roasting converts coffee beans from green to ripe, rich in aroma and flavor, but do you know what happens during roasting?

When we bake beans, it is mainly divided into physical and chemical changes

Changes in volume and pores

Coffee beans rank at the top of the plant kingdom for cell wall strength, and they have a tough outer layer of material that increases their stiffness and strength.

When coffee is roasted, elevated temperatures and the process of converting water into gas raise the pressure inside the coffee bean. These conditions change the structure of the cell wall from rigid to rubbery, because coffee beans contain polysaccharides (bound carbohydrate molecules).

The internal material is pushed toward the cell wall, leaving a gas-filled void in the center. This means that the beans expand in volume as their mass decreases, and most of the gas buildup is carbon dioxide released after roasting.

Roasting also increases the porosity of coffee beans, making them less dense and more soluble. Of course, this also had a lot to do with Han Fei, who turned them into delicious dishes.

Changes in oil

Coffee beans contain oils, and during roasting, the high pressure inside causes these compounds to move from the center of the cell to the surface.

Oil helps retain volatile compounds inside the cell, which are chemicals with high volatility at room temperature that are essential to producing coffee's aroma and aroma, molecules that might dissipate rapidly without oil.

The longer the roasting time, the more obvious the structural transformation, the lower the density of the coffee beans, and the more gas they produce. The longer the roasting time, the more fat the coffee beans will have on the surface.

These developments partly explain why dark roast coffee tastes different from light roast coffee.

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