Where does coffee bitterness come from? What factors will produce coffee beans in the process of roasting and making

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Coffee is best known for its bitterness, but caffeine actually accounts for at most 10 percent. This can be seen from the fact that roasted beans contain caffeine concentrations that are not affected by roasting, and decaffeinated coffee also has bitter tastes.

One of the sources of coffee bitterness is brown pigment.

Brown pigments can be classified according to molecular size, and the larger the molecule, the more bitter it is. In the case of coffee, deep roasting increases brown pigment, followed by larger (more bitter) pigments. When you cook deep-baked beans in daily life, you will find that the bitterness is stronger and the taste is stronger.

In fact, Arabica and Robusta species differ in bitterness intensity and taste. This is also due to the amount of brown pigment and molecular size caused by different. Robusta species have lower oligosaccharide content than Arabica species, do not caramelize, and easily produce larger molecular pigments, so even if lightly baked, they often taste bitter.

Another source of bitterness is the cyclization of seven diamino acids produced when amino acids and proteins are heated. This is a combination of two amino acids. Different combinations will cause different bitterness intensity.

According to German scientists, the bitter taste of coffee comes from chlorogenic acid lactone. Chlorogenic acid lactone

It is found in most plants and is produced by plants during aerobic respiration.

Chlorogenic acid lactones increase gradually as coffee beans are roasted and made. That is to say, mild and moderate roasting will make chlorogenic acid lactones produce a relatively mild bitterness. With the increase of roasting time, chlorogenic acid will decompose again and become vinyl catechol polymers. This chemical molecule is coffee concentrate.

The source of bitter taste.