Will the water quality change affect the flavor of coffee extraction? What kind of water should be used to make a single black coffee by hand?

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Guide reading

A cup of coffee consists of 98% water and 2% flavor substances. Water is used as a solvent to dissolve and extract the flavor substances of coffee powder. in addition to water temperature, water quality will also affect the extraction of coffee.

In this paper, the front street uses two kinds of direct drinking water commonly used in home / office-pure water and mountain spring water to compare to see what effect different water has on the extraction of coffee.

What factors in the water affect the extraction of coffee?

TDS (Total dissolved solids)

TDS said the water contains dissolved substances: inorganic salts and organic matter, which are mainly composed of calcium, magnesium, sodium, potassium ions and carbonate ions, bicarbonate ions and so on. The higher the quality of TDS, the more dissolved matter in the water. TDS is measured in mg/l (mg / L) and concentration in ppm. "1mg/l=1ppm"

The more dissolved substances in the water, the more flavor the coffee will be extracted. But too much dissolved matter can cause coffee to taste miscellaneous and even bitter. On the contrary, the less dissolved matter in the water, the coffee is prone to insufficient extraction.

PH value (pH)

Acidity and alkalinity, also known as hydrogen ion concentration index, is a scale of hydrogen ion activity in solution. Whether the aqueous solution is acidic or alkaline is completely determined by the relative content of H + and OH- in the solution: neutral (ph=7) when OH- = H +, alkaline when OH- > H + (ph > 7), and acidic when OH- < H + (ph < 7).

Coffee is a low-acid drink (PH value 5-6). If we use water with ph > 7 to brew coffee, it will increase the PH value of coffee and reduce the sour taste of coffee, thus affecting the overall flavor performance of coffee.

Cooking experiment

In the communication with enthusiasts, Qianjie baristas found that most of the coffee brewed every day uses buckets of pure water / mountain spring water. So this article focuses on testing the difference between the flavor of the same coffee bean cooked in these two different kinds of water.

Firstly, the TDS pen is used to test the water quality.

The TDS of purified water is 0ppm, that is, drinking water with zero impurities after all the dissolved substances in the water are removed by reverse osmosis technology.

The TDS of mountain spring water is 37ppm, that is, mountain spring water with a small amount of dissolved matter after purification.

PH value

According to the information provided on the packaging of drinking water, the PH value of pure water used in Qianjie is 7.1 ±0.5, and that of mountain spring water is 7.3 ±0.5. Both of them are neutral water.

Cooking object & cooking parameters

This time, Qianjie will use V60 to cook Huakui 5.0 coffee beans from Ethiopia. The brewing parameters are: coffee powder 15g, powder-water ratio 1:15, grindness 0.85mm sieve pass rate 80% (about fine sugar thickness), water temperature 90 ℃.

Cooking technique: three-stage extraction. Steam with 30 grams of water for 30 seconds, small flow circle injection to 125 grams, continue to inject water to 225 grams when the water level is about to be exposed, remove the filter cup when the water level is about to expose the powder bed, (the time of steaming starts) the extraction time is 2: 01 ".

Pure water cooking flavor

Light berry aroma, citrus sour taste, honey sweet, the flavor is concentrated in the front and middle, there is a light tea back sweet at the end, the flavor is flat, the taste is thin, and the fermentation feeling of sun-treated coffee beans is not reflected.

Sweetness: ☆☆

Acidity: ☆☆☆

Bitterness: ☆

Alcohol thickness: ☆☆

Mountain spring water cooking flavor

Floral aromas, sweet and sour aromas of berries, citrus and plums, mango juice, honey and a sweet finish of black tea, full taste, clean flavor, long finish, comfortable and pleasant overall feeling.

Sweetness: ☆☆☆☆

Acidity: ☆☆

Bitterness: ☆

Alcohol thickness: ☆☆☆☆

From the coffee flavor performance of the two kinds of water quality, we can see that the sour taste of the coffee brewed from the mountain spring water is softer than the pure water, and the sweetness is more obvious, and the mellow thickness and aftertaste have a good performance. On the other hand, the coffee brewed with pure water is slightly thin, with a prominent sour taste and a feeling of water as a whole.

Experiments show that pure water is not suitable for brewing coffee, water containing an appropriate amount of dissolved matter will be conducive to the extraction of coffee. If there is no mountain spring water, filtered water can be used for cooking.

Qianjie is not recommended to use unfiltered tap water or mineral water for brewing, because these two kinds of water have a high content of dissolved matter, which will affect the thermokinetic extraction ability of coffee, resulting in a change in coffee flavor.

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