Good morning. I posted only coffee roasting every day, but I would like to write about extraction today. There are various factors that determine the taste of coffee.

### Bean cultivation and harvest method, green bean storage, roasting, bean extraction
###
Through these processes, a cup of coffee comes into our hands. When each of these elements changes, the taste of the coffee changes. Extraction can also make such a change. For example, a variety of roasted green beans that taste good with a buttery feel can be reduced by controlling the extraction. On the other hand, it is possible to slow down the acidity by controlling the extraction of strong and bright acidified beans. You can control the basic light taste of coffee and the taste of darkness to some extent.

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Pour-over extraction is one of the easiest ways to extract coffee at home. With a little interest and control, I have the advantage of expressing the coffee feel I want. The hand drip is slightly different from the hand drip. The hand drip is slower than the dripping hot water by carefully adjusting the flow rate. Hand Drip has the advantage of controlling various flavors according to the personality and skill of the extractor, but it can be difficult to adjust the taste and concentration of coffee if it is wrong. On the other hand, PourOver has the advantage of being able to extract good flavor even for those who first contact the coffee by adjusting the extraction time, grinding, and extraction amount to some extent. But there are lots of things to worry about in both ways. Let's take a look at the various figures in the photo above.

### coffee
The amount of bean used in the extraction. Weighing is essential to maintain consistent taste balance. You can maintain a nice balance of taste even if you follow only the weight and temperature of the professional barista.

### Brew water
The total amount of water to put into the coffee powder. It means that 300ml of the total was poured and extracted. We used 300ml of water for 20g of bean, but the ratio of bean and water is 1:15. Usually the preferred ratio is 1:15 to 17 in the café. There are many places where 1:10 ~ 12 are used to pursue a deep style of coffee.

### Beverage
It is the amount that comes out when we put 300ml of water. This means the amount of coffee that can be extracted completely and put in our hands.

### Time
The total time spent extracting. Basically, it is easy to extract in order of sourness - sweetness - bitter taste. In other words, on average, the shorter the extraction time, the better the sour taste than the bitter taste. Conversely, if you continue to increase the extraction time, you will get more caffeine extracts and more components such as bitter taste.

If you use this principle well, it is easy to extract coffee according to my taste. If you have a sour taste and you want to increase the extraction time, you will feel less acidity. (Sour taste is extracted first, then sweet taste extraction is done in the second half, and taste is neutralized. In contrast, you can choose a method to reduce the extraction time so that you can feel the sourness of the bean that lacks sourness more and the bitter taste.

### TDS
Abbreviation of Total Dissolved Solid, meaning coffee solids dissolved in coffee. If the TDS is too low, the coffee will feel less, and if it is too high, the balance of coffee flavor will be broken and extracted, making it difficult to feel the correct taste. Usually 1 ~ 1.6% of the extraction is done to fit.

### ext.
The extraction yield. What is the total amount of ingredients extracted from the coffee powder? If the extraction yield is too low, the coffee flavor will become tender and it will be difficult to feel the correct taste. On the contrary, if the extraction yield is high, the bad bitter taste of the bean, the taste of the wood, and other unpleasant flavors are extracted together. Usually, it is about 17 ~ 22%, and it is extracted, and the yield is controlled according to the taste and kind of the bean.

### Degrees
The temperature at which water is first introduced. For best accuracy, it is best to use a drip port that keeps the temperature constant, such as Bonavita. However, since the boiling water is usually put into the ordinary drip port and extracted, the temperature decreases with time. Traditional temperatures range from 88 to 93 degrees. Weakly roasted beans are advantageous to keep the flavor balance by extracting higher water temperatures.

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Let's take a look at the extraction order.
We used roasted coffee beans from Burundi  AA Specialty. Because the roasting time and DTR are very short, I increased the water input temperature somewhat higher than usual.

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### Rinsing
Rinsing. The first step is to soak the paper in water. Some people do rinsing, others do not. I usually do rinsing to reduce paper flavor.

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###  Bloom & stirring
 To extract the ingredients of the bean more easily and to remove unnecessary gas in advance. Add 1.5 to 2 times as much water as the beans and lightly stir. The reason for stir is to make enough water to reach the bottom bean powder.

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Wait a moment. Usually it takes about 30 ~ 40 seconds. In case of roasted beans with short DTR, it takes longer time.

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### Extract
Start extracting. It is best to use the balance or you have to adjust it with the scale of the drip server. Since the target of water injection is 300ml, we will divide into 150ml twice. Though it is not specially decided, I usually split water twice. You can adjust the total extraction time by decreasing or increasing the number of times the water is filled.

It causes turbulence after water is introduced. The turbulence is turned by a spoon, while the surface is slightly twisted, and when the water is stirred, the water rotates down due to the rib shape of the Hario Dripper. The reason for this turbulence is to take the extraction more aggressively and extract it evenly for each bean particle. Turning more aggressively to the ground beans, turbulence will increase the extraction yield. If you want to extract a thicker, larger amount of coffee flavor, aggressively mix water and bean flour and wait for the water to spin. But if it is wrong, it can be extracted and the bad taste can be extracted.

The extraction is usually completed in 2 to 3 minutes. Depending on the roasting / grinding / aging conditions, the time is shorter and longer. Like a cooking recipe, you can get a consistent taste by adjusting the extraction time, the amount of bean / water, and the temperature of the water.

I will stay here today. I will post about the pour-over setting method according to the degree of roasting next time. Thank you for reading the long story. :)

https://www.youtube.com/watch?v=P6S5_QHWdPs&t=23s