The source of the bitterness of coffee? Why is coffee bitter?

Everyone thinks that caffeine is the cause of the bitter taste of coffee, but in fact, caffeine accounts for only 10% of the bitter ingredients. As we said earlier, the concentration of caffeine in roasted beans is not affected by the degree of roasting, and decaf coffee also tastes bitter, so we can be sure that caffeine is not the whole cause of bitterness. So what is the remaining 90% bitterness?

One of the root causes of the bitterness of coffee is brown pigment. Brown pigments are also roughly classified according to molecular size, and macromolecular brown pigments are more bitter. With the deepening of the baking degree, the amount of brown pigment will increase, and the proportion of macromolecular brown pigment will also increase. So deep-roasted coffee beans are more bitter and textured-which is consistent with our daily impressions.

The bitterness and texture of Arabica and Robeska are different, which is caused by the difference in the quantity and molecular size of brown pigment. Because the sugar content of Robeska is lower than that of Arabica, it is not easy to "caramelize", so it is easy to form macromolecular brown pigment, so the baked Kanefa is more bitter.

Another reason for bitterness is the "cyclic diaminic acid" formed by amino acids and proteins after heating. If the molecular structure is different, the degree of bitterness is also different. In addition to coffee, this ingredient is also found in the same bitter cocoa and dark beer.

Can we artificially control the bitterness? The answer is, of course, yes. We can control the bitterness by changing the type, baking degree and baking method of coffee beans. in addition, changing the extraction method can also control the bitterness of coffee to a certain extent.