In the early days, the coffee culture in China was not as widespread as it is today, and there were only a few coffee shops opened in the country, let alone roasters of coffee beans.
As a result, people at that time had to go to the supermarket and buy nitrogen-filled or vacuum-packed coffee beans if they wanted to make their own coffee at home. These beans are often more than two months old, and although they have not passed their expiration date, we can imagine what kind of taste the beans will taste after two months. 
The picture cuts back to today's savage growth of the coffee industry, in the bustling streets, specialty coffee shops are eager to dominate all the stores on the entire road, and there are more and more small private coffee roasters, which can't help but make us feel that people have been deeply affected by coffee culture. As a result, people began to pay attention to the freshness of coffee beans and no longer buy beans that were produced too old. 
The simple reason is that freshly roasted coffee beans have a richer layer of flavor. But here's the problem: people are looking for fresh coffee beans while demanding them to be less fresh??? 
What the! Is this a freshly baked bean? No! Give it a few days and I'll drink it again in a few days".
What are the downsides of coffee beans being too fresh? Bad flavor :Freshly baked coffee beans contain a lot of carbon dioxide, which will hinder the extraction of aromatic substances from the coffee beans by hot water.
Dryness:The dryness here refers to the feeling of drinking, when you finish drinking coffee, there will be a trace of discomfort left in the mouth and throat, similar to the negative feeling of stuck throat and dryness. These are due to the effects of the coffee bean's residual roasting aroma being incorporated into the coffee. 
So how should we respond? Raising beans is the best choice to deal with these two problems! When we receive the beans we have purchased, the first thing we do is to check the roast date (i.e. the production date). If it is not long after it has just been baked, then it is best not to open the package, and leave it for a few days to raise beans, 5 to 7 days from the roasting date (hand poured, Italian universal). 
Because coffee beans will emit a lot of gases in their bodies during the period of time they have just been roasted. When the gas emissions are about the same, we go to brew it. In this way, not only does there be no dryness, but it is also easier to extract the aromatic substances of the coffee, and the flavor of the brewed coffee will be fuller and richer!
What should I do if I'm in a hurry and want to brew a fresh pot of coffee right away? If you are a beginner, it is also recommended to brew the beans in a conventional way when they are freshly baked to taste the "taste" of fresh beans. If you're just looking to satisfy your appetite, then you might as well give it a try
"Pre" grinding:The reason why the flavor of hanging ear coffee is not outstanding is because after grinding, the coffee particles will be emitted gas, and when you have done a series of operations, the aroma has already run away! So, when you want to make coffee with fresh coffee beans, you might as well leave it for 30 to 60 seconds after grinding, which can effectively reduce the dryness of the coffee caused by fresh roasting! 
Extend the simmering time:The main job of steaming is to remove the carbon dioxide from the coffee beans, paving the way for better extraction for subsequent brewing. So, we just need to extend the sourming time by a few seconds and expel more gas, which will reduce the extraction effect of the gas. 
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