The basic chemical reaction that takes place during coffee roasting the degree of coffee bean roaster

I, when heated, is converted into isomers cellulose III and cellulose IV. The structure of coffee is a well-developed matrix, which improves the consistency of quality and contributes to the uniform spread of heat during baking. Cellulose exists in coffee in the form of embedded in lignocellulose (an amorphous matrix containing hemicellulose and cellulose-containing lignin), which form matrix unit walls (cell walls). Hemicellulase (hemicellusloses) is a polysaccharide composed of bifurcated sugar and uronic acid. Lignin is particularly noteworthy because it is a highly polymerized aromatic substance. When the distribution temperature exceeds 446 degrees Fahrenheit (230 degrees Celsius) and the surface temperature of beans exceeds 536 degrees Fahrenheit (280 degrees Celsius), the cell wall is severely damaged. The actual temperature will change according to other factors. The second explosion associated with deep baking is the rupture of this matrix, which may be accompanied by volatilization of lignin and other aromatic hydrocarbons. Under controlled roasting conditions, the ambient temperature of beans should never exceed 536 degrees Fahrenheit (280 degrees Celsius). A wider safety line should limit the maximum ambient temperature to 520 degrees Fahrenheit (271.1 degrees Celsius). These temperature restrictions can minimize the damage to the cell matrix, increase the complexity of performance in the cup, increase the roasting yield and the shelf life cycle of the product.

When the bean temperature > 100℃, the color of raw beans changes from green to yellow, and when the moisture is on, it is lost for dehydration, resulting in a smell similar to that of baked bread.

Bean temperature > 120,130 ℃, raw bean color changes to light brown.

The bean temperature is about 150℃ to produce the smell of stir-fried barley.

The bean temperature is about 180 ℃ and begins to produce green smoke. The first explosion begins to produce chemical pyrolysis reaction, which releases a large amount of CO2. The burst sound occurs, the color turns brown, and the size of the bean increases.

The bean temperature is about 210 ℃, the first explosion is over, and the color continues to darken.

The second explosion of the bean temperature was about 220℃ ~ 230℃. The color continued to become dark and dark brown, and oil appeared on the surface of the coffee bean.

The bean temperature is about 240℃ ~ 270℃. Although the temperature increases, the darker the bean color, the more gas is released, the volume continues to expand, the coffee bean surface oils out, and the coffee aroma changes fully.

The bean temperature is about 270℃ to stop releasing smoke, the color is black, the appearance becomes dark, and the volume is no longer larger.

The bean temperature is about 300 ℃. The beans are black, puffy and fragile, and the aroma disappears completely and becomes carbonized.

The general actual baking temperature range is 185-240 ℃. In addition to the influence of temperature on the flavor of coffee, the way and equipment of roasting also have an effect.