What are the most overlooked details of roasting coffee? How much is the effect of preheating and cooling on baking?

The preheating and cooling process of coffee roasting is small, but important. One of these is the beginning of coffee roasting: providing the drum with the right temperature, while the other is the final part of coffee roasting: maintaining the flavor of the coffee and bringing about sudden changes in the temperature of the coffee beans. Sounds interesting, let's talk a little more today!

About preheating and drum temperature settings

When we are ready to roast coffee, we need to weigh green beans and load them into the hopper. Although they are ready to be placed into the drum, sometimes it may take a while to wait. Why is that?

This is because the roaster must be preheated to the set temperature and reach the drum set temperature before putting the coffee beans into the drum. Just like cooking, we never put steak on a cold plate. If we preheat the oven before baking the cake, the cake will be better when placed in the oven. Coffee roasting works on a similar principle to cooking: it definitely requires a preheating process.

Preheating and drum setting temperatures vary depending on the characteristics of the green beans, weather, humidity, how many green beans we bake, etc. The preheating process will help create the baked profile.

Key: Cooling process

Whether green, to-be-roasted or roasted, they are all very susceptible to temperature. When the temperature changes, the beans being baked will undergo physical and chemical changes. Even though the roasting is almost complete, we still need to pay attention to the temperature of the beans.

Cooling is an important process in coffee roasting. When coffee beans fall out of the barrel, they can reach temperatures of at least 210 degrees Celsius or higher. Therefore, if the cooling process is not fast enough, the beans can continue to cook in the cooling dish. It produces a malt or rye bread taste, which is what toasters should avoid.

Usually, there are two main ways to cool beans: by air or water. At Coffee Roasters in Asia, we use the air-cooled method. There is a cooler under the cooling tray and an agitator in the cooling tray. When we want to exit beans, we will need to press buttons and make them run. These tools help cool the beans immediately. Fast and efficient.

The cooling process usually takes 4 minutes. When finished, we need to put the coffee beans into sealed bags to keep them fresh.