Discover the secrets of making a good cup of coffee

Brewing delicious coffee is much easier than roasting good beans, because the variables of brewing coffee are simpler and easier to control, unlike roasting which is often affected by the moisture content of the beans, softness and hardness, climate, fire power, exhaust valve, and the patency of the exhaust pipe.

The variables for brewing a good cup of coffee are nothing more than the freshness of the beans, the weight ratio of coffee beans to water, the extraction time, the extraction temperature, the grinding coarseness, etc. With a little attention, you can control these variables and brew a good cup of coffee in a casual manner. The most precious acidic aroma of specialty coffee also has different extraction concentrations due to water temperature, brewing time and grinding coarseness.

TIPS:

The concentration of acidic aroma in a cup of coffee is as follows:

▼Chlorogenic acid about 1000 mg/L Quinic acid 490 mg/L Citric acid 460 mg/L Acetic acid 220 mg/L Lactic acid 190 mg/L Malic acid 130 mg/L Phosphoric acid 77 mg/L

Fresh beans are a must

Prerequisites for aromatic coffee

Even if you are good at brewing coffee, it is useless if you encounter off-flavor beans. The best tasting period for coffee is within 7 days after it is roasted. After a week, the aroma gradually ages or disappears, and even goes off-flavor. The heavily roasted beans at the end of the second crack are more susceptible to oxidation and off-flavor than the lightly roasted beans before the second crack, and it is difficult to keep them fresh.

Whether fresh beans are brewed by hand, French filter press, siphon or espresso machine, the coffee powder will easily swell and have a thick "foam layer" (crema, or oil foam).

If the beans are not fresh, the coffee powder will not rise easily, and may even sink, and the "foam layer" will become thin. This is because the carbon dioxide contained in the fresh coffee has been exhaled, taking away a large amount of aroma or being oxidized, leaving only carbonization, bitterness and caffeine, which is not worth drinking.

▶How to judge the freshness of coffee beans in the online shopping era? Click on the previous article: How to choose fresh coffee beans in the online shopping era

If the roasted beans can be consumed within two weeks, they can be stored in a one-way degassing valve bag or sealed can at room temperature. If you buy too much and cannot finish it within two weeks, it is best to divide it into several small sealed cans and put them in the refrigerator to keep them fresh, so as to avoid the breeding of ochratoxins in high temperature and high humidity, which is harmful to health.

Putting small cans in the refrigerator and opening another can after finishing one can can reduce moisture and oxidation. According to research by American coffee expert Michael Sivetz, refrigeration can indeed extend the tasting period of coffee.

▶To know more about coffee bean storage, click on the historical article: Coffee bean storage guide in different situations

Coffee bean to water weight ratio

The strength of coffee greatly affects the flavor

For hand-brewed coffee beans, French press or siphon brewing methods, the ratio of coffee beans to extraction water should be between 1:10 and 1:17. Those who prefer a stronger taste may wish to use a ratio of 1:10 to 1:12, i.e. the optimal extraction water volume for 15 grams of coffee beans is between 150 and 180 milliliters, or 150 milliliters of water with 9 to 15 grams of coffee beans.

However, some people who love strong coffee use a ratio of 1:8, that is, 150 ml is brewed with 18 grams of coffee beans. For those who prefer a lighter taste, you can dilute it slightly with a ratio of 1:13 to 1:17. If it exceeds this limit, it will be too thin and tasteless. However, the ratio of coffee beans to water in an American filter coffee machine is between 1:17 and 1:23.

How to adjust the extraction rate?

1. Adjust the grinding degree (that is, the contact area between coffee and water);

2. Adjust the brewing time (that is, the contact time between coffee and water);

3. Adjust the water temperature

Strength: The weight of coffee ingredients as a percentage of the total coffee liquid weight.

For example, a 200-gram cup of coffee may have a coffee concentration of only 1.2-1.5%, that is, the weight of the coffee component in this cup of coffee is only 2.4-3 grams, and the remaining 197-197.6 grams are water.

Extraction time and coarseness

The coarseness of the coffee grind should be proportional to the extraction time

That is, the finer the grind, the easier it is for the aromatic components to be extracted by hot water, so the extraction time should be shorter to avoid over-extraction and bitter taste. On the contrary, the coarser the grind, the harder it is for the aromatic components to be extracted, so the extraction time should be longer to avoid under-extraction and tastelessness.

Italian espresso is extracted at 92°C under high pressure, and 30 ml of it is extracted in 20 to 30 seconds. This is the shortest extraction time of all brewing methods, so the grinding fineness is finer than that of siphon, hand brewing, moka pot or French press.

Siphon and pour-over are very popular in Taiwan, China. The coarseness of the two is similar (about 3 to 4 on the scale of the Pegasus grinder). Although the brewing time of siphon is two minutes shorter than that of pour-over, the grind should be finer, but the extraction temperature of siphon is about 10℃ higher than that of pour-over, thus offsetting the factor of fine grinding.

The brewing time of the pour-over pot is about two minutes longer than that of the siphon pot, but the brewing water temperature is lower, which offsets the coarse grind factor, which is quite interesting.

Extraction temperature and roasting degree

The degree of coffee bean roasting should be inversely proportional to the brewing water temperature

That is, the water temperature for extracting dark roasted beans should be lower than that for extracting light roasted beans. Because dark roasted beans have more carbonization, too high water temperature will highlight the bitter taste. On the contrary, light roasted beans have rich acid aroma. Too low water temperature will turn the lively and rising acid aroma into dead acid and astringent. Therefore, the water temperature for extracting light roasted beans should be higher, and the water temperature for brewing dark roasted beans should be slightly lower.

In addition, the higher the water temperature, the shorter the extraction time. This is why the brewing time of a siphon pot (extraction temperature is about 90℃~93℃) is 40 to 60 seconds, which is shorter than the brewing time of a hand-poured pot (extraction temperature is about 80℃~87℃), which is about two minutes.

How to make a good espresso

First of all, you need good green coffee beans and good roasting, and you also need a proper bean-raising period;

Secondly, you need a good grinder and appropriate grinding scale to ensure the completeness of the extraction. With a good grinder, a highly stable coffee machine can ensure that a cup of high-quality ESP can be produced continuously to ensure the uniformity of extraction.

On this basis, having excellent water purification and softening equipment can improve the taste of the whole cup of coffee to a certain extent. After all, 99% of the ingredients in a cup of coffee are water;