Brief introduction of the factors affecting Coffee extraction and the influence of Water temperature on Coffee extraction

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Qianjie Coffee-factors affecting the extraction of shared Coffee

1. The ratio of coffee to water:

To put it simply, in the same 150ml cup, the higher the coffee content, the stronger the taste, while the more the water content, the lighter the taste. Like ordinary drip coffee, we want a sweet and refreshing taste, so we use a lower coffee-to-water ratio, while espresso aims to extract coffee as syrup-like coffee in a short time, so use a higher coffee-to-water ratio. In the case of a cup of coffee, we expect that the weight of coffee released into the water is about 22% of that of coffee. It can also be said that the exchange rate of coffee and water, we expect to fall in the range of 18 murmurs 22%. To grasp this standard, it is usually recommended that the ratio of coffee to water is 1:15. Of course, this number is quite flexible. We often adjust the ratio of coffee to water according to individual taste, water temperature, degree of grinding and degree of roasting. After many fine-tuning, we find out the most appropriate ratio of coffee to water that suits our own taste.

two。 Grinding thickness and extraction time:

Coarser grinding requires a longer soaking time to release the taste of coffee into the water, extracted by soaking, such as pressure kettle, siphon pot is ideal for coarse ground coffee, because the contact surface between coffee and water is small, so let the water pass too quickly, it is difficult for coffee to have proper contact time with water to dissolve the taste into the water. On the other hand, the use of finely ground coffee will save time for coffee to come into contact with water. If you use the way of soaking, there will be excessive extraction. So we usually use a method that allows water to come into contact with coffee quickly and flow out quickly. Such as hand flushing or concentrated extraction.

As for the grinding degree, how much should be adjusted? Because everyone uses different equipment, it is not fair to say which bean grinder or coffee machine is more standard. It is suggested that the thickness should be adjusted according to the extraction method and personal taste.

3. Proper extraction operation

1. Estimate the degree of grinding of coffee and the time of coffee in contact with water. As mentioned in the previous paragraph, the cooking methods suitable for rough grinding and fine grinding are different, and a little carelessness may lead to insufficient or over-extraction.

2. The temperature of water. The higher temperature will shorten the extraction time, while the lower temperature we need to extend the extraction time to obtain the ideal extraction degree. In terms of water temperature, we usually recommend falling between 85 degrees Celsius and 94 degrees Celsius, in other words, boiling water is not an ideal choice for coffee extraction, because too high temperature will seriously shorten the extraction time, so excessive extraction often occurs, resulting in reduced aroma, poor flavor, and bulky taste.

3. Pre-immersion. In order to soak the coffee evenly, we often wet the coffee first, let the water flow through the coffee once, tidy up the contact surface between the coffee and water, and then formally extract it. We often use this technique when using hand pots, and some people call it "steaming". Similarly, when using a siphon pot, we also use this technique to smooth the contact surface between water and coffee in order to achieve the purpose of balanced extraction.

4. Ideal extraction method

i. Immersion type: nothing is more representative than the pressure kettle. Let the coffee soak in hot water for a period of time and then filter out.

ii. Cooking method: people who often watch European costume movies will have seen the protagonist put coffee and water in a pot and cook it directly on the stove. Use slow heating and hot convection in water to extract coffee.

iii. Osmosis: the principle of mocha pot belongs to osmosis. Heat the hot water vapor into the metal tube, flow the coffee evenly through the filter, and finally the extracted coffee liquid flows out from the outlet of the upper pot.

iv. Drip filter: both hand-made and American coffee machines belong to this method, which drips hot water into the coffee and uses the physical nature of the water to extract the coffee from the top down.

v. Vacuum filtration: the siphon kettle is the most representative tool for this kind of extraction. Using the principle of thermal expansion and cold shrinkage and the phenomenon of vaporization, the hot water is pumped from the lower pot into the upper pot, and then the lower pot is cooled after the extraction is completed, and then the water is sucked back to the lower pot by vacuum extraction.

5. Good water quality

The weight of water in a cup of coffee accounts for 98%! So we can say that the quality of water affects 98% of coffee. In addition to pure water, there are many kinds of minerals and, of course, some microbes in the water we use. Because coffee is very sensitive, too much or too little minerals will affect the taste of coffee. If the mineral content is too high, it can even damage our equipment (especially the espresso machine, where calcium is the killer of the machine). Therefore, it is very important for us to soften and filter the water quality.

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