How to use the ATAGO TDS measuring instrument? How to calculate gold cup extraction | Coffee extraction

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Today, a fan asked Qianjie Coffee, how to use the TDS meter for coffee? So today Qianjie Coffee would like to share with you how this instrument is used and what is its use?

Coffee concentration meter

In fact, the principle of light refraction is used to measure the total amount of dissolved solids in water. We can see that the concentration meter says: Brix, TDS.

Brix: the concentration of soluble solids in the sample. Soluble solids refer to sugars, salts, proteins, acids and other substances that are soluble in water.

TDS: the ratio of soluble matter to water in a cup of coffee. The higher the TDS value, the more dissolved matter the water contains.

Qianjie Coffee gives you a general introduction to the coffee concentration meter, and then shows you how to use it: 1. Press "START" to turn on the machine, drop the pure water to the refractive crystal, and correct it by "ZERO".

2. After mixing the brewed coffee, immediately take out about 1g of liquid and place it for about a minute, let the temperature of the coffee liquid drop, and then drop it to the refractive crystal, press "START" to start the test, and wait a few seconds to get the results.

Remember to clean it up with water or alcohol after use, so what is the use of these values for us? After measuring these parameters, we can calculate the extraction rate of coffee!

Extraction rate: indicates the proportion of the weight lost in the brewing process of coffee beans to the use of coffee beans. To put it simply, it is used to brew coffee powder, and what percentage of the substance is dissolved in the coffee.

For example, when you use 100g of coffee powder for brewing, after brewing the coffee, remove the moisture from the coffee grounds (whether dried or dried), if there is 80g left, which means that 20g of the substance is dissolved in the coffee. Then the extraction rate of this cup of coffee is 20%. In the world of coffee, there is a concept called Golden Cup Theory!

In the actual coffee extraction, in order to pursue the better taste of coffee, we should not only strive for the original taste of coffee, but also avoid producing bad taste. There are several widely accepted criteria for the proportion of trade-offs, which is the legendary Glod Cup theory. The Golden Cup Theory (Gold Cup) holds that "good coffee" must meet two conditions at the same time:

1. The extraction rate is between 18% and 22%.

two。 The coffee concentration is in the range of 1.2% to 1.45%.

Calculation formula: (coffee liquid weight * TDS%) powder weight = extraction rate

The coffee with insufficient extraction (the extraction rate is less than 18%) is usually sour, thin, light, monotonous and uncharacteristic, while the coffee with excessive extraction (the extraction rate is higher than 22%) is more bitter, gray and astringent. As far as dripping coffee is concerned, to put it simply, the powder-to-water ratio between 1:15 and 1:22 can be generally called the golden cup range, but it does not mean that this ratio is the golden cup. In addition, the powder-to-water ratio is not equal to the powder-to-liquid ratio, and even less equal to the concentration. On the contrary, the standard gold cup powder-to-water ratio will basically be within the above range.

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