The influence of water quality on coffee brewing what kind of water is better for brewing coffee

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

01 | Preface

We know that the main factors affecting coffee are origin, roasting, grinding, water temperature, proportion, brewing method, freshness, and water quality. No matter what kind of factors, all from a scientific point of view to study the impact of various factors on the flavor of coffee, we should return to the essence. The method of our research is generally to use the method of single variable to understand the influence of certain factors.

What is the effect of water quality on coffee? In this article, I would like to study the reasons for coffee extraction around water quality:

About 98% of a cup of coffee is water, and less than 2% of the coffee content can make a big difference to the whole cup of coffee. Most people think that water only acts as a carrier and has little effect on coffee flavor.

The impact on the study of water quality is more difficult than other factors, water looks the same, it is impossible to identify the difference of its internal composition with the naked eye.

In fact, [most people don't pay attention to the influence of water] is the main reason why I write about water quality.

02 | know water

I believe that most people have the experience of drinking water sweet. So the question is, why does pure water taste a little sweet?

The following is what I think I agree with:

In fact, the water treated by the pure water machine (built-in reverse osmosis membrane) will not have any taste, it should be tasteless to be exact. Many people think that the treated water has a "sweet" taste, in fact, the original drinking water contains too many impurities, taste or peculiar smell, for a long time, affecting the taste buds to accurately judge the taste of water.

In this case, the drinking water suddenly becomes much cleaner, this contrast is the fundamental reason why you feel that the water has a sweet taste, the reason is that simple.

Before knowing water, we need to understand the factors that affect water quality: TDS, hardness (GH), pH (pH value).

Hardness (GH)

Soft water:

Water that contains no or less soluble calcium and magnesium compounds is called soft water.

Hard water:

Hard water refers to water that contains more, soluble, calcium and magnesium compounds.

TDS:

Also known as the total amount of dissolved solids, the higher the TDs value, the more dissolved matter in the water, including both inorganic and organic matter, measured in milligrams per liter (mg/L).

A unit of concentration per million of PPM solution. Refers to the number of milliliters of solute in 1 million ml solution or indicates the number of grams of solute in 1 million grams of solution.

Conversion relationship: 1mg/l=1PPM

PH value:

Also known as hydrogen ion concentration index: a scale of hydrogen ion activity in a solution, that is, a measure of the acidity and basicity of a solution in a general sense.

03 | how water affects the extraction of coffee

According to the theory of coffee extraction, we know

When the TDs is too high, the minerals in the water are oversaturated and there is not enough room to extract the flavor from the coffee (mentioned in "water for coffee")

If the TDS value is too low, the penetration capacity of water may not be enough, resulting in insufficient extraction.

In the past, I thought that the lower the TDS, the easier it should be to extract because of the difference in concentration. Why is it easy to cause insufficient extraction?

The point is: some compounds in hard water are "sticky" and they hold on to the compounds in the coffee during the coffee making process. Calcium and magnesium are particularly sticky, and if the water contains a lot of magnesium ions, coffee has a stronger flavor and higher caffeine. However, hard water also has more carbonates, which Hunton found may be the source of the more bitter taste of coffee. Soft water tends to have a lot of sodium, but they are not sticky (it doesn't help to extract good or bad ingredients from coffee).

According to the SCA study, the ppm value of water is between 125and 175. it is most ideal to extract coffee. If the ppm value is less than 75, it is more likely to be overextracted. If the ppm value is higher than 225ppm, it is more likely to be underextracted.

Summary: TDS affects coffee extraction relatively, depending on the proportion of good ingredients in your water that are conducive to the extraction of coffee. (for example, the low value of TDs and the content of calcium and magnesium ions are beneficial to the extraction of coffee.)

04 | Experimental verification

Test equipment:

Qu so-and-so brand distilled water, some sweet mountain spring, smart cup, TDS detector pen.

The reason for choice: distilled water is the most extreme soft water, does not contain any substance, and is more contrastive; some sweet mountain spring has a low TDs value, but the content of calcium and magnesium is relatively high, and it is rumored that its mineral composition and proportion are the most suitable for coffee extraction; smart cup immersion extraction can reduce the test error caused by manipulation.

TDS Test:

Distilled water:

Some sweet mountain spring:

A little sweet soluble matter data:

Cooking data:

Experimental coffee beans: sun 90 + candle candle (baking date 5.19)

Cooking method: hand flushing

Degree of grinding: 4W (BG)

Smart cup, 18 grams of powder, water temperature 90 degrees, ratio of water to powder close to 1:16

Steaming in 45 grams of water for 20 seconds

After injecting water into 288ml, the total time is 3 minutes.

Test group 1 (distilled water):

Flavor description:

Wet fragrance is floral, light berry fragrance, the entrance has obvious citrus acid, citrus sweet, taste clean, mellow, the flavor is concentrated in front of the interruption, there is a touch of sweet at the end, there is no obvious characteristics of sun-cured beans, more like washed beans.

Sweetness: ☆☆

Acidity: ☆☆☆☆

Bitterness: ☆

Alcohol thickness: ☆☆

Test group 2 (mountain spring water):

Flavor description:

The acidity is relatively weak, the imported sucrose is sweet, the honey is sweet, the palate is rich with weight, the taste is clean and lingering, and the overall feeling is comfortable and pleasant.

Sweetness: ☆☆☆☆

Acidity: ☆☆

Bitterness: ☆

Alcohol thickness: ☆☆☆☆

Contrastive conclusion:

The coffee brewed from the mountain spring is less acidic than distilled water, but its sweetness is much higher, and the body performance is almost perfect, including the aftertaste.

The coffee made from distilled water is not as extracted as I imagined. It seems to have extracted the front and middle part of the coffee. It shows a strong sense of acidity, middle sweetness, clean, bright and unique flavor. The reason why the acidity of the coffee washed out from the mountain spring is relatively weak is that its excellent sweetness exceeds the acid it has, but the coffee washed out from the mountain spring has a strong sense of weight and high sweetness, which further shows that the extraction rate of mountain spring water is higher than that of distilled water. This also proves that the relatively low TDS and viscous dissolved substances are more conducive to the extraction of coffee.

| 05 | end |

With regard to the effect of water quality on coffee, the conclusion of this paper may only be applicable to some conditions, and the conclusion may be one-sided and correct. But the fun of coffee is here, we go to verify our doubts, keep learning, keep knowing.

Related recommendation: is hand-made coffee really good? Why does coffee smell better than it tastes?