What is the first crack and how to judge it? This is a conclusion that requires some practical experience and combined with your own perception. So today I will talk to you in more detail about what is the so-called “first crack”.
We sometimes hear bosses in cafes say that their own beans are roasted until they pop. The “first crack” when roasting beans mentioned here is a sound that occurs at a critical stage in the coffee roasting process. It is indeed a “burst” sound. This is a signal sound because it can help roast beans Let the chef know the progress of their roast, and let them know what to do next. And this kind of sound is produced because the coffee beans absorb heat from the roasting process, the coffee beans receive heat from the roaster inside, convert the internal moisture into steam, and start to release heat outward, which is a plosive sound produced by the exothermic process.
Usually, the first crack of coffee beans is at a temperature of about 190°C. When the first crack is about to happen, the roaster usually reduces the heat of roasting this time, and when the first crack is over, some roasters may stop roasting completely. , put the beans to cool down. So the first crack is very important for any roasting process, it is almost a watershed in the presentation of flavor.
I think when and exactly how the first crack happens depends on the characteristics of the coffee being roasted and how the roaster heats up. In some roasting-related sharing articles, it is mentioned that the time for the first crack of coffee beans depends on how the heat is transferred. Sometimes it is a long and loose crackling sound, which requires more development time. Sometimes the first crack is done quickly at the same time, which may mean that the heat is pushed too fast in the early stages. To identify whether the first crack is coming, you can experience it through the smell, the critical point when you smell the smell from toast to caramel, or just pull out the beans with the sampling spoon of the roaster to see look at the state of the beans.
After the first crack of coffee beans, it will continue to be heated. At this time, the gas (mainly carbon dioxide) in the coffee beans will be pressurized, so that when the structure of the beans cannot withstand it, a second crack will be produced. Usually what we call light roasting is mostly after the first crack and before the second crack.
With people’s in-depth understanding of fine coffee, in fact, they do not focus so much on the so-called light-roasted beans, but dark-roasted beans are not good. There is no difference between good and bad, only the difference in flavor preference and taste characteristics. Some people compare a bean baker to “make up” for green beans. You have to express the “character” and unique flavor memory of the bean through makeup. And the understanding of flavor characteristics, as long as the good flavor is expressed, it doesn’t matter whether it is the first or second crack of beans.
Here is a video about the changing process of coffee beans: https://youtu.be/Nu_TVVCCHeQ