The secrets of coffee flavor that 99% of people don’t know are hidden here!

If you often drink coffee, you must have experienced such questions:

This coffee is too strong, too bitter, too weak...

Today, Xiao U is here to chat with you.

Deciding on coffee flavor

The most critical step - extraction

extraction

The word extraction comes from Latin, which means to squeeze something out or obtain an extract. In chemistry, extraction refers to obtaining valuable substances (flavors) from raw materials (coffee beans).

There are many different methods of extraction, the most common of which is to use hot water to extract the flavors from the ground coffee. Brewing is often used instead of the word extraction.

Coffee bean extraction concentration

No coffee bean can be completely extracted into coffee liquid, because only 30% of the substances in a coffee bean can be extracted, and the remaining 70% or so is wood fiber that is insoluble in water.

As for the extraction standard, the "Golden Cup Extraction Theory" issued by an international organization stipulates that the actual extraction rate of a cup of coffee should reach 18%-22% as the best extraction standard, and the concentration of "substances extracted from coffee" in a cup of coffee is only 1.15%-1.35% (don't be surprised that about 98% of the coffee we drink is water), so it is not best to extract all 30% of the water-soluble substances in each coffee bean.

However, the seemingly extremely concentrated espresso and the relatively strong coffee liquid made by the moka pot do not reach the level of "complete extraction", and their extraction rates will be in the range of 18%-22%.

The "strength" of espresso is simply a greatly reduced proportion of water in a cup of coffee. After all, a cup of espresso only has a capacity of a few dozen milliliters.

Golden Cup Extraction Theory

Moreover, it often only takes tens of seconds to make a cup of espresso, and you can get a cup of extremely concentrated coffee, thanks to its 9 atmospheres of pressure and high-temperature extraction process.

For hand-brewed coffee, the extraction rate is controlled by the size of the water flow, precise control of the temperature, and the degree of stirring. As long as the extraction rate and concentration reach 18%-22% and 1.15%-1.35% respectively, it is a good cup of coffee that meets the requirements of the "Golden Cup Extraction Theory".

Over extraction

This means that the coffee grounds are in contact with the hot water for too long, or the ratio of coffee grounds to water is too low. When using a drip coffee machine and brewing espresso, over-extraction is caused by grinding too finely.

When brewing by hand, it may be that the extraction time is too long. Water temperature that is too high can also lead to over-extraction. Over-extraction will extract too many unwanted chemicals, such as caffeine, and make the coffee taste bitter and unbalanced.

Insufficient extraction

It means that the coffee grounds are in contact with the hot water for too short a time to extract all the flavor from the coffee grounds, which will make the coffee taste thin, bitter and unbalanced.

Underextraction can also be caused by grinding too coarsely or the water temperature is too low. If the ratio of coffee powder to water is too high, you will get under-extracted espresso. Such coffee not only lacks the characteristics of coffee, but also tastes bitter.

Extraction time

This refers to the time that the coffee powder is in contact with water. It is an important variable for good coffee. Other terms such as brewing time or soaking time also refer to extraction time.

That’s all I have to say about extraction today. Have you marked all the knowledge points?

I am knowledge point

Only 30% of the coffee beans can be extracted, and the remaining 70% is wood fiber that is insoluble in water.

Golden Cup Extraction Theory: The actual extraction rate of a cup of coffee should reach 18%-22% as the optimal extraction standard

Both over-extraction and under-extraction can cause coffee to taste bitter.