Is coffee acidic or alkaline? What if the coffee turns sour? What does the sour coffee mean?

"Boss, why is the breakfast coffee sour today? I don't like it. Can you give me a cup of coffee that is not sour?" Many people have this experience when drinking coffee in a cafe.

Most people mistakenly think that coffee is sour if it is not fresh, and sour coffee is not good. This is really a great smear and misunderstanding! In fact, coffee itself is an acidic drink, whether coffee is sour or not depends on the baking degree of beans. The longer the roasting time is, the higher the caramelization degree is, the more acidic substances are destroyed, the less sour the coffee is, the shorter the baking time is, the lower the caramelization degree is, and the less acidic substances are destroyed. It is easy to make sour coffee, that is to say, the roasting degree is inversely proportional to the sour taste. The deeper the roasted coffee is, the more sour the coffee is, and the shallower the roasted beans are. In addition, the temperature of brewing coffee also has an effect. Water with a lower temperature is certainly more likely to make sour coffee than a slightly higher water temperature. I am afraid that the sour people had better drink the coffee while it is hot, otherwise the sour taste of the coffee will appear as the temperature drops.

The preference of coffee roasting degree from country to country often varies from region to region. In principle, the baking degree in Italy is getting deeper and deeper from north to south. Milan in the north of Italy is roasted deeply, and the coffee is slightly sour, while Rome in the south is heavy-roasted and the coffee has no sour taste. The roasting of coffee in the United States is getting lighter and shallower from west to east, that is to say, the roasting degree of West Bank cities such as San Francisco and Seattle is deeper than that of New York or Washington. West Bank coffee is darker and more bitter than the East Coast, while the East Coast prefers a more lively sour taste, mostly deep roasting or shallow roasting. The baking degree in Taiwan is deeper in the south than in the north. There is no market for sour coffee in southern Taiwan, but there are a small number of eosinophiles in northern Taiwan, and shallow roasting is still a small market. Caffeic acid is not a criterion for judging whether the quality is good or bad or whether it is fresh or not. it is all a matter of subjective taste. If you are afraid of acid, you will choose deep baked beans or Asian beans, and if you are acidophilic, you will drink shallow baked beans or African beans.

In fact, high-quality shallow roasted coffee shows a lively sour taste, rather than a dead acid in the end. The tip and both sides of the tongue are stimulated by fruit acid to secrete saliva. However, the sour taste disappears in a few seconds, transforming into the spicy aroma of green pepper. Or lemon, citrus-like fragrance, and finally show the sweet aftertaste of chocolate, like going through an ever-changing taste journey.

The sour taste of shallow roasted coffee can also be defined by technology, that is, the so-called PH value (pH value). The pH reading is from 0 to 14. The higher the value, the lower the acidity and the stronger the basicity. Pure water is neutral, and the pH is 7. The PH value of sour lemon juice is about 2, the PH value of tomato is about 4, and the pH value of fresh milk is above 6.5. What is the PH value of coffee drinks? It depends on the degree of baking.

For breakfast coffee with shallow roasting degree, the pH value of Full City is between 4.5 and 4.7, the pH value of medium and deep roasted coffee is about 5 to 5.5, and the PH of deep roasting (Dark Roast) is above 5.5. As far as ordinary people's taste buds are concerned, when the pH value of the beverage exceeds 5.5, it is difficult to detect its sour taste, and the pH value of heavy baked beans is often more than 5.5, so it is not easy to drink sour taste. Human taste buds can easily taste sour when the pH is less than 5, so shallow baked beans will have a sour taste.

Source:

The blog of many people's coffee shops in Qingdao.