Coffee explosion time Why coffee beans burst is not obvious how long does it take for coffee beans to explode

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Let's take a look at what happens to coffee beans when they warm up to explode during coffee roasting.

Baking is a process of heating beans. Unbaked raw beans smell only a little grassy and slightly fruity, but taste almost meaningless. Through the heating process, baking causes a series of complex chemical changes inside the beans, which in turn releases the various flavors that were originally locked in the raw beans.

With regard to the importance of coffee roasting, there is a saying that the baker determines 80% of the flavor, while the pot coffee thinks that the nature of the raw beans is good enough, and the baker will want to retain more local layers of origin, so the closer it is to the flavor of the producing area, it is not easy to take into account the roaster's baking style.

According to the different heating time and speed, it can be divided into different baking degrees. The most common and easiest method is to divide it into shallow, medium and deep ones, with the following features:

Shallow baked Light Roast

In recent years, the trend of boutique coffee is mostly towards shallow roasting, because shallow roasting can not only retain the most acidity and aroma, but also retain the most flavor from the producing areas, that is, the growing environment of coffee, which brings unique personality to beans. Coffee beans appear light brown in appearance and will not have a glossy finish.

Medium baked Medium Roast

Coffee beans to the degree of roasting, will begin to produce "caramelization" phenomenon, the acid begins to weaken, mellow taste stronger, so there is a sweet taste, coffee beans will have a little bit of oil on the surface.

Deep baked Dark Roast

The deeper the baking, the more you need to rely on the experience and skills of the baker, so the more you can show the personal color of the baker, usually with a thick taste and throat rhyme. The deeper the baking, the more obvious the bitterness, and the bean surface will be glossy, dark brown, or even close to charcoal black.

In the process of roasting, after the coffee beans are warmed up, they enter a process of volume expansion, and as the water reaches the boiling point, it continues to change into steam, and because the coffee beans are in a rubber state, the beans have good scalability. At this time, the coffee beans are constantly enlarged by water vapor, and the expansion rate of coffee beans increases rapidly. During this period, although Meina's reaction is very slow. But the reaction time will affect the amount of substances after chlorogenic acid hydrolysis, thus affecting the change of flavor, of course, most of the flavor is still not suitable for drinking, and then we continue to bake, coffee beans will enter the yellow point this stage. The water of the fiber structure of coffee beans has almost evaporated. Because the rubber state of coffee beans is not over, the beans will slowly shrink and wrinkle because of water loss, and the amount of heat supply at this time. It determines the degree of caramel reaction. The caramel reaction takes precedence over Mina's reaction, so the time during this period determines the extent of Mina's reaction. If it passes too quickly during this period, it is easy to cause the bean surface to quickly enter the second glass state, thus affecting the water discharge of the bean core.

The rate of caramel reaction after the yellow dot determines the rate of carbon dioxide production, and the output of carbon dioxide determines the degree of wrinkle of coffee beans, so "the fold before explosion represents the degree of caramel reaction and the amount of sugar left."

Digression: if we give more heat to coffee beans during this period, there will be a situation in which the first explosion and the second explosion will come at the same time. Of course, in this case, because coffee beans are still acidic, it will lead to high levels of phenols, there will be a lot of unpleasant substances, and coffee beans will exudate a lot of oil (a mixture of oil and guaiacol, etc.) due to high temperatures. So it's a dark cup of coffee.