Recently, a number of friends who bought beans asked Qianjie in the background of a treasure: "Qianjie Qianjie, is the quality control of your beans a little wrong recently?" Why doesn't the brewed coffee taste as good as it used to be? ”
To be reasonable, the roaster already has beans on his back, is it deep baking? This pot, he won't be able to carry another black pot! 
In fact, this is the same principle as the recent frequent adsorption of coffee powder - the weather cools down. I don't know if you still remember, but two months ago, Qianjie wrote a note about cooling, which roughly described the impact of cooling. So today, let's elaborate on why it has such a big impact on the taste of coffee after cooling down! Increase in hypothermia rate
After cooling, the rate of hypothermia is naturally greatly improved. What does the rate of hypothermia affect for extraction? That's right, the hot water we use when brewing, it is not in a constant state of heat retention, at a room temperature of more than 20 degrees, 500ml of hot water will drop the temperature at a rate of about 3 °C per minute. When we brew a pot of coffee, if we use a three-stage formula, then the water temperature has actually dropped to 89°C when the third stage is filled.
Now that the room temperature drops below 10°C, the deheating of hot water is faster! Compared to the previous one, 500ml of hot water now drops the temperature at a rate of about 5°C per minute. Therefore, if we apply the original water temperature to brew the coffee, then the extraction rate will naturally be lower than the previous one, the extraction rate will be lower, and the flavor will not be so full. Therefore, there are several ways we can improve the changes brought about by the decrease in temperature! 1. Preheat the spout
I didn't expect it! The first is not to raise the temperature of the water Before brewing, the spout is at room temperature, and it does not heat itself because of the presence of hot water in the pot. Therefore, before brewing, we can pour out a little hot water to preheat it and reduce its impact on the steaming hot water.
2. Increase the water temperature
Since it cools down so quickly, we might as well raise the water temperature to correct its effects. Increasing the water temperature by 1 2°C on top of the water used in conventional brewing will correct for the drop in temperature and get the extraction back on track. For example, we used to use 92°C hot water for brewing, but we can raise it to 93°C when the room temperature is low!
3. Increase the amount of water
The rate at which hot water cools down is affected by the amount of water, and the more water, the slower it will cool down! As we mentioned above, 500ml of hot water will drop by about 5°C per minute at room temperature of 10°C, and if you increase the amount of water to 700ml, then it will drop by about 3°C per minute. However, it should be noted that the increased amount of water must be controlled under the condition of its own strength load.
4. Reduce the height of the brew
Remember Matsuya-style brewing invented by Mr. Yoshikazu Matsushita? It's the way to simmer with a lid! In addition to this peculiar way of steaming, the height of his water injection is also a breathtaking part. Because, his water injection height is about 20 30cm!
The reason why the water injection height is extended is to allow the hot water to contact more air and lower the temperature! What we need to do is to reduce the height of the water injection and reduce the cold air that the hot water comes into contact with! 
The water temperature we mentioned earlier is measured before brewing, and it starts to cool down the moment it pours out of the spout and touches the air! The larger the surface area of the water column exposed to the air, the more obvious the cooling will be, so we need to lower the water injection height. 
If you are worried that the pressure is too low and the water flow is not impactful, then we can increase the inclination of the pot body to make up for the reduction of the impact
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