The fourth Golden Cup Theory of Coffee: the calculation of extraction rate of hand-brewed Coffee

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We begin to implement it now, first of all, we will discuss the calculation of extraction rate by hand flushing method. Some people may wonder why we need to discuss the extraction rate by different cooking methods. And we will soon find that the calculation of extraction rate by hand method is basically the extraction rate calculation method recognized by most people. However, if you use this method to calculate the extraction rate of Syphon, AeroPress and other cooking methods, it may be wrong! I think many coffee connoisseurs use a higher amount of coffee powder than a hand pot when brewing with Syphon. If you use the manual method to calculate the extraction rate, you may mistakenly think that it is insufficient extraction, and then use various brutal methods to get a "correct" but "strange to drink" extraction rate! What is the reason for this? We'll explain it next time.

Today, let's start with the standard hand punch method. In fact, even if there are many "interesting" (that is, complex) aspects of the hand punch method, we are a simple version today, and then the mouth version will certainly explain the complete calculation in detail.

The standard extraction rate formula for hand flushing pot is very simple, that is:

Formula of extraction rate by hand pulsing method

[example]

Use 30g of coffee powder, brew 400g of coffee, and the TDS concentration is 1.5%. If we calculate the extraction rate, it will be:

400 x 0.015 / 30 = 0.2

That's 20%, perfect extraction rate!

Wait, isn't that how we calculated in the first place? Yes, this is the standard extraction rate algorithm. But once again, this can only be used in hand flushing (of course, the same is true of American coffee machines that imitate hand flushing). Another important point is that you must calculate the weight of the "finished coffee". In other words, you may want to know the weight of the pot you use, finally measure the coffee + the weight of the pot, and then deduct the weight of the pot.

Generally speaking, this simple calculation is not bad. But many times, we want to know:

I want to make a cup of coffee (236cc). If the concentration of TDS is 1.5%, how much powder and how much water will it take?

If my coffee is stronger (lighter), how much do I have to catch gouache?

To put it simply, in practice, we certainly want to know how much water we need when we make it, and it is convenient for us to control it when we make it. In addition, we will also want to pre-calculate the appropriate ratio of water to powder (the ratio of water to coffee powder), that is, our brewing formula. When it is too strong and too light, we also want to know how to make adjustments to make it possible to flush out a little lighter or thicker, but extract the right coffee.