A complete guide to coffee

This article is a bit long. It contains almost all the basic knowledge you should know about coffee. Through this article, you can at least answer the following questions:

What exactly are we drinking in the coffee market?

What is the process from planting coffee beans to making a cup of coffee?

What are the factors that affect the taste of coffee?

How to choose coffee beans?

What are the ways to make coffee at home?

How to evaluate the taste of a cup of coffee?

If you are interested in the above questions, you can read on. This article is about 6000 words and the reading time is expected to be 25 minutes. The whole article is divided into four parts: the types of coffee on the market, the selection of coffee beans (baking of types and origin), the brewing method of coffee and the evaluation of coffee flavor. You can only look at the parts you are interested in according to your needs.

Due to space constraints, this article is only a brief combing and summary. If you want to know more details, please search through keywords by yourself.

1. Coffee on the market: what are we drinking when we have coffee?

Each cup of coffee needs to go through the following four processes:

① (manor) coffee tree planting → ② (manor) processing coffee fruit into raw coffee beans → ③ (coffee bean dealer) roasting coffee beans → ④ (coffee shop / food processing plant) making coffee drinks

① ② coffee planting and raw bean processing will be mentioned in Chapter 2, ③ coffee bean baking will be mentioned in Chapter 3, let’s take a look at ④ the production of coffee drinks.

The coffee we drink on the market can be simply divided into processed coffee drinks and on-site coffee.

・ processed coffee drinks and instant coffee powder:

Such coffee can be easily bought in supermarkets and convenience stores, such as Nestle coffee. Most products use cheap coffee beans as raw materials in the production process. This kind of coffee beans, mainly robusta varieties, tastes very ordinary, but because they are easy to grow, high yield and low price, they have become the first choice for processing coffee. In addition to the cost, the shelf life should also be considered. Therefore, this kind of coffee will certainly contain many additives such as syrup and milk slurry.

We should all know the characteristics of this kind of coffee. Their taste is very different from that of the coffee we drink in the cafe. Such coffee can never reflect the unique flavor of coffee. If you just want to supplement caffeine or want to drink coffee flavored drinks, you can buy such coffee.

・ ready made coffee sold in coffee shops / convenience stores:

According to the production method, now made coffee can be divided into two categories: espresso and brew.

Espresso is also often called espresso. The reason why it is called concentration can be simply understood as extracting the taste of coffee beans into a small amount of water as much as possible. Therefore, concentration generally requires deep baking + fine grinding of coffee beans, and the production process is under high pressure to ensure the full extraction of the taste in coffee beans. Generally, the machine for making espresso in coffee shops is relatively large. It depends on the machine to make high-quality espresso. Of course, espresso can also be made by hand (full immersion).

You can learn the knowledge of “deep baking”, “fine grinding” and “full immersion” mentioned here.

An espresso machine spirit Duette (photo from pixabay. Com)

You may drink a cup of espresso that is small and bitter, then find that you don’t like coffee at all, and then wonder why the word espresso is so famous in the coffee industry. In fact, the coffee mixed drinks we usually drink, such as latte and cappuccino, are made of espresso. In addition, the so-called American coffee (coffee Americano, an Italian name) is also formed by mixing espresso with water. The coffee capsule used in the coffee machine can also be regarded as espresso in essence.

Espresso is a big category. Why espresso is so widely used, in addition to the rich taste and raw materials suitable for other coffee drinks, another important reason is deep baking. Deep baking has two advantages: 1. The taste of coffee beans is easy to control, and the taste difference of coffee produced will be very small (low failure rate). 2. It is most suitable for preservation and transportation. The best use of deep roasted coffee beans is to make espresso. Therefore, coffee chains, without exception, focus on espresso for two reasons: taste quality control and raw material preservation.

The extracted coffee will keep the ground coffee and water soaked for a certain time during the production process, so that the flavor of coffee beans can be fully dissolved in the water. This process of dissolution and absorption is called extraction. The classification of enrichment and extraction may be confusing. Isn’t the process of making espresso extraction? We can see a picture from Starbucks to understand the difference between concentration and extraction.


In short, concentration pursues to extract as much coffee flavor from coffee beans as possible, while extraction pursues to give full play to the flavor other than coffee flavor. Therefore, the coffee made by the two methods tastes very different.

From the production method, extracted coffee can also be divided into two categories: immersion and drip.

When it comes to extracted coffee, everyone is talking about manual coffee by default. In fact, the extraction process can be manual or machine. Starbucks or convenience stores, for example, also have drip filtered extracted coffee, which is made by machines (fresh blended coffee is called in Starbucks). Starbucks selection is manual, at least I have Starbucks r in Japan). However, coffee masters will dislike the bitter taste of machine-made extracted coffee, which is completely inferior to that of handmade coffee (otherwise the barista will lose his job).

I think the biggest problem that machine extraction affects the taste is actually coffee beans. I just mentioned the reason when talking about espresso. For example, coffee chain stores will use deep roasted coffee beans to ensure the transportation and preservation of a large number of coffee beans and maintain the same coffee taste. Coffee beans will lose a lot of flavor after deep baking.

Compared with espresso, the biggest advantage of extracted coffee is that it can extract the complex flavor of coffee and distinguish the characteristics of different coffee beans. In addition to the bitter and sour coffee, extracted coffee can also taste sweetness, flower flavor, fruit flavor and so on. Extracted coffee / handmade coffee is the core of the so-called modern boutique coffee. The most talked about hand brewed coffee (water injection type) and the siphon pot that looks like a chemical experiment (full immersion type) all belong to extracted coffee.

In addition, it’s best to drink extracted coffee directly. Its fun is to experience the most subtle taste difference of coffee, so don’t add milk and so on.

Supplement 1: intentional coffee (espresso) and American coffee (espresso with water), so what is “French coffee”?

Although the word caf é (French coffee) is also very common in many French cafes, there is no French coffee to be exact. There are only French toast coffee and French press. French baking is a kind of deep baking, while French pressing method is a complete immersion extraction method. Whether it is deep baking or French pressing, the final coffee is rich and bitter.

Supplement 2: what is black coffee?

White coffee, as opposed to black coffee, actually refers to the combination of coffee and milk. Therefore, black coffee can be directly understood as pure coffee. The combination of coffee and milk is also a big category in coffee, but it is not involved in this article. You can find the information yourself. It is worth mentioning that in addition to the common lattes and cappuccinos, the popular Australian white coffee “Australian white” or flat white in recent years is also a mixture of coffee and milk. Have you ever heard of Malaysian white coffee? Malaysian white coffee is a kind of instant coffee, which is made of coffee powder and creamer.

Through the above chapter, you may have a certain understanding of the coffee you have drunk. Next, come to a conclusion before talking about the following content. Personally, I think there are three important factors affecting the taste of coffee:

Coffee bean variety origin + baking degree + production method (including grinding fineness)

Many high-quality coffee courses refine the factors affecting coffee taste to various details, such as equipment, water quality, water temperature, and even the air pressure of the indoor environment. These factors do affect the taste of coffee, but they are not the factors that determine and change the taste of coffee. For example, the taste of the water used will certainly affect the taste of coffee, but no matter how good the spring water can change the sour coffee into bitter coffee. These too mysterious things are not discussed in this article. The factors that have the greatest impact on the taste of coffee are the three points I listed above:

Variety and origin of coffee beans: orange in the South and orange in the north. The characteristics of coffee beans from different varieties and different producing areas (main factors affecting producing areas: soil environment, temperature, light and altitude) are different, and the way from coffee fruit processing to raw coffee beans will also directly affect the taste of coffee beans. It’s like tomatoes in orchards and tomatoes grown at home.

Baking degree: baking is actually easy to understand. The degree of baking from light to deep means that the taste of coffee changes from fresh to rich. The degree of roasting controls the different expression tendencies of coffee beans, just like the difference between fresh ketchup and canned ketchup.

Brewing method: espresso and extracted coffee were mentioned in the previous chapter, and there are obvious differences in taste. The difference between soaking type and water injection type of extracted coffee is also very different. The brewing method affects how the taste of coffee beans dissolves into the water. It’s like different tomato dishes.

Next, let’s talk about coffee beans, baking and making methods.

2. Selection of coffee beans:

2.1 varieties of coffee beans

Coffee trees are widely planted in subtropical to equatorial areas (23 ° s-23 ° n). Places with high sunshine, high latitude and volcanic soil are conducive to coffee planting. It is said that coffee originated in Ethiopia and then migrated from Ethiopia to other countries. Modern coffee varieties can be traced back to the source of three varieties. However, in Ethiopia, there are some varieties that do not belong to these three sources.

The three sources are Arabica, Robusta and Liberica. Liberica is a relatively small variety. Robusta is a cheap but easy to grow and high-yield variety mentioned earlier. It is often used as a coffee drink with processed instant coffee powder. The current boutique coffee basically refers to Arabica coffee beans (net red coffee shop% Arabica name, do you understand…).

Arabica is mainly composed of typica and bourbon, as well as their new hybrid varieties. Not belonging to these two categories, there is a variety called Gesha, which has a small output, a small number and a high price.

https://en.wikipedia.org/wiki/List_ of_ coffee_ varieties

The figure above is relatively small. Please open it through the connection. We don’t need to spend time remembering the names, places of origin and taste characteristics of different varieties. We just need to know that there are two categories: typical and Bourbon. After that, when you slowly come into contact with your favorite coffee beans, you can understand the specific origin and variety name.

Supplement 3: what is the legendary Blue Mountain coffee?

Through this figure, we will find that blue mountain coffee is actually a variant of typical. It belongs to Jamaica’s high altitude coffee. Blue Mountain coffee production is not high, and 90% is only exported to Japan. Because Japan has provided financial and technical assistance to Jamaica, Blue Mountain coffee is contracted by Japanese coffee dealers.

2.2 origin of coffee beans

Arabica coffee beans are famous in the following places:

North America: Hawaii, Mexico

Central America: Costa Rica, Guatemala, Panama, Jamaica

South America: Brazil, Colombia, Bolivia

Africa: Ethiopia, Congo, Kenya

Asia: Indonesia (Java, Sumatra)

In addition, Vietnam is also a big country producing coffee beans, but the coffee grown in Vietnam is mainly cheap robusta. Yunnan in China can also grow coffee from the geographical environment. Starbucks in China sells coffee beans from Yunnan, but I haven’t tried.

Supplement 4: what is Vietnamese coffee?

Vietnamese coffee is classified as a kind of water filled coffee. Generally, the shop will make it for you on site. Vietnamese coffee is characterized by tin iron filter, and water is injected only once. At the same time, Vietnamese coffee will add condensed milk, so it can also be called “white coffee”. I have not investigated whether Robusta coffee beans are used in Vietnamese coffee. It is estimated that each store will be different.

2.3 coffee bean processing method

After the coffee fruit is picked, the peel and pulp of the coffee fruit need to be removed before it becomes a coffee bean. Processing is generally the work of planting the manor. The manor processes the coffee fruit into dry coffee beans, and then sells and transports them. The processing methods of each plantation will be different, and different processing methods will affect the taste of coffee to a certain extent.

Maybe you didn’t know that fresh coffee fruit looks like this? photo from pixabay.com

The processed green coffee beans grow like this (picture from the Internet)

Processing methods are mainly divided into three categories:

·Wet / washed: the process of coffee bean processing is to peel the flesh with a pulp separator → take out the coffee beans after fermentation → dry them in the sun. Most coffee in the world is washed. The water washing method can make the origin characteristics, variety characteristics and sour taste of coffee shine in the coffee cup. This is also a strictly controlled method, which can make the flavor of the same batch of coffee consistent. In addition, removing the pulp first and then drying the beans can reduce the probability of making mistakes.

·Dry / natural: before the invention of the pulp separation machine, all coffee used the sun treatment method – after picking the coffee fruit, the pulp is not removed, but the coffee fruit is dried to the extent that it can be peeled by the machine. Because of this, the taste of coffee fruit will enter the beans during drying, rather than being washed away by water washing. The flavor brought by sun treatment is very unique. It has stronger fruit flavor and lower acidity than washed beans.

·Pulp sun treatment / Honey & Honey natural: its treatment process is similar to the water washing method. The difference is that after the peel of coffee is stripped by the pulp separator, it directly enters the drying stage, and part of the pulp is still intact. Honey treated coffee beans have some washing characteristics and some sun exposure characteristics, which not only retain the acidity of washed coffee, but also obtain the alcohol thickness, sweetness and earthiness of sun exposure coffee, but lack of strong fruit flavor.

The above description is basically copied from the book handmade coffee. To sum up:

The water washing method is more modern and scientific. When drying, there is no skin or pulp. The beans have the same taste and high acidity.

The sun drying method is to dry the pulp with a belt. The taste of the pulp will get into the coffee beans. The coffee will have fruit aroma, but the acidity is low.

Honey treatment is a mixture of the two, without belt pulp, retaining acidity and sweetness, but losing fruit aroma.

Supplement 5: what is kopi luwak / civet coffee?

Coffee beans are fed to a cat named civet to let the cat’s stomach digest the peel and pulp of coffee fruit. Coffee beans cannot be digested by the cat and are discharged through feces. Therefore, it is named cat excrement coffee. Therefore, cat excrement coffee is actually a special processing method of coffee beans. Cat excrement coffee is produced in Indonesia and the Philippines. Through this “biological fermentation” peeling and meat removal method, coffee beans have a special taste. Cat excrement coffee is expensive because of its small output. It has a unique taste, but there are different opinions. In this way, it is actually very cruel for wild animals to keep coffee fruits in captivity and force them to feed.

2.4 baking level

Basically, you can master it all by looking at the following picture.

Source: https://www.wlscook.com.tw/tips_ detail.php?doc=26

A brief summary of baking:

The black coffee beans we often see are actually deep roasted coffee beans. The degree of roasting can be judged by the color of coffee beans.

The words “first explosion” and “second explosion” are not used in this picture, but you may see them elsewhere. Explosion refers to the phenomenon that coffee beans will be dried and cracked during baking. The first crack is called “explosion”. We use this word to distinguish the baking progress.

The two strongest flavors of coffee – bitter and sour – are controlled by the degree of roasting. Simply put, baking degree is inversely proportional to acidity and directly proportional to bitterness.

The roasting process also means that the plant activity of coffee beans decreases. Therefore, in addition to acid and bitterness, the shallower the baking, the more you can taste the plant flavor of coffee, such as fragrant flowers; The deeper the baking, the more you can taste the burnt flavor, such as chocolate and smoke.

There are some special English terms for baking. You can pay attention to them so that you can identify them when you buy imported coffee beans.

2.5 how to choose coffee beans

The coffee beans we buy are actually roasted, so we need to choose the coffee we want from the perspectives of origin, variety and baking (of course, including weight and price). When we buy coffee beans, we need to know these important information from the package:

Bean ingredients: blend or single origin. Blend refers to a mixed formula containing more than 2 kinds of coffee beans. The purpose of mixed coffee is to better control the desired acidity and bitterness through the matching of different coffee beans. Single is a single coffee bean variety.

About coffee beans: variety, origin, processing method and flavor. Because most of the packages will introduce the flavor of this variety of coffee beans, we don’t need to remember the characteristics of coffee beans from different origins and varieties.

About baking: baking degree, baking time. The baking date is more like the coffee generation date. Baking time also affects the taste of coffee. One theory is that the peak freshness of coffee beans is between 7 and 10 days after baking. Freshly baked coffee beans are not suitable for making coffee immediately. They need to be placed for a period of time to stabilize the taste.

Pictures from the Internet

3. Coffee making

This section does not introduce the manufacturing method of any machine, but only involves the manual manufacturing method. The manual production method is divided into grinding and brewing.

3.1 grinding

Grinding is an early preparation in the brewing process. The required thickness is only related to your production method (production tool). Different appliances require different grinding degrees. Refer to the following figure:

The picture comes from the book handmade coffee

Example of grinding degree (source: http://www.bcoffee.cn/index.php?s=/Index/Document/detail/id/7082.html )

When buying coffee beans, try not to buy ground ones. Because the ground coffee powder will quickly release the taste of coffee, especially light baking, the fresher the coffee beans, the faster they deteriorate. On the contrary, ground coffee powder is basically only deeply roasted. It is recommended to buy a bean grinder and grind it yourself, so that coffee beans can be saved more conveniently. There are manual and automatic grinders. Generally, the thickness can be adjusted. Manual grinders will be much cheaper. If you don’t have a bean grinder, you can grind it into powder on site according to your own brewing method. The ground powder should be drunk as soon as possible.

Although the grinding degree is divided into several grades, there is no absolute division. And when hand grinding, coarse grinding may also be mixed with fine grinding powder. Therefore, there is no need to be too tangled. Select a rough degree from coarse to fine, grind it several times and adjust it slowly. Water injection appliances generally use medium grinding. Choose medium coarse or medium fine according to the number of holes in your filter cup. The most fundamental is to affect the speed of water flow and brewing time. Generally, the selected fine grinding degree of a hole.

Coarse grinding is easy to retain the original plant flavor of coffee beans, while fine grinding is easier to extract coffee flavor and release more caffeine. Therefore, generally speaking, coarse grinding is suitable for shallow baking, while fine grinding is suitable for deep baking, but it is not absolute. As mentioned before, espresso is superfine ground, because superfine grinding is easier to absorb the taste of coffee. Therefore, choosing the appliance is equal to choosing the grinding method and determining the taste preference.

Storage: coffee beans / ground powder are best packed in a one-way breathable bag because it will slowly release gas.

English words corresponding to various grinding degrees: coarse / medium coarse / medium fine / fine / extra fine

Packing bag with unidirectional vent hole

3.2 brewing method

In fact, the first part has talked about a lot of coffee making process. From the perspective of coffee extraction degree, it can be divided into espresso and brew. From the perspective of tools, it can also be divided into machine and manual. The extracted coffee can be divided into two types: immersion and drip.

I think the best way to learn brewing methods is to find videos online. Take drip filtration brewing as an example. The process of making coffee is usually 3-5 minutes, so the video with explanation should not exceed 10 minutes.


The complete soaking method is actually very simple, just like making tea. Let the coffee powder soak in hot water for a certain time, and then separate the coffee powder to make a cup of coffee. Just master the ratio of water to coffee powder, water temperature and soaking time. Common tools for making fully soaked coffee include: AeroPress, press pot and syphon / vacuum. There are obvious differences in the taste of coffee made by these three methods.

Press pot is to filter out coffee powder after full immersion. The production process is relatively simple, but it is easy to leave residue and over extraction.

Press the kettle. Pictures from the Internet

The biggest difference between AeroPress and French pressure pot is that pressure is used to accelerate the extraction process. There will be no residue in the prepared coffee, and the extraction degree is easier to control. It is worth mentioning that love pressure can make a cup of espresso.

Love pressure. Pictures from the Internet

Simply put, syphon / vacuum is to heat and expand the gas in the sealed container, flush the boiled water into the container with coffee powder to soak, and then turn off the fire to cool and shrink the air, so that the brewed coffee can return to the previous container. This process makes brewing and filtering coffee automatic. The siphon pot needs heat source, which is the most expensive in manual coffee. At the same time, the extraction time should be adjusted by water temperature or heating degree, and the brewing technical requirements are also the most difficult.

All kinds of siphon pots come from the Internet

Supplement 6: what is cold brew?

Cold extract coffee is also a kind of fully soaked coffee. Literally, it means soaking coffee powder in cold water or even ice water. Because of cold water immersion, the release of taste in coffee becomes slow, so it usually takes more than half a day to make cold extract. Because there is no hot water to oxidize the coffee, the taste of cold extracted coffee will be more mild.

Supplement 7: what is Turkish coffee?

Turkish coffee is a completely soaked coffee. Different from the ordinary full immersion method, Turkish coffee is finely ground, mixed with hot water, put into a small copper pot, and then heated until boiling. The coffee needs to boil three times before it is ready, and the coffee powder will not be filtered after it is ready. It can be thought that Turkish coffee is completely over extracted, and the taste will be particularly strong and bitter. Therefore, it is usually boiled with sugar. After saccharification, the coffee will become very thick. Interestingly, after the viscous Turkish coffee is poured into the cup, the residue will be left in the coffee pot, and the Turks will predict their fate through the shape of the residue.

Water injection trickle filter (drip):

Water infusion and drip filtration brewing is also the hand brewing coffee we often hear. Spread filter paper on the filter cup, pour coffee powder and add water. Water injection brewing is to control the whole extraction process through the speed of water injection. The filter cup has various shapes, including single hole and multi hole. Different filter cups need different grinding degrees (see the matching drawing of the grinding part above), which also affects the water flow speed / soaking time and the contact area between coffee powder and water. In order to better control the water flow, it is best to use a fine beaked pot.

There are two key steps in water infusion coffee brewing. The first is to wet the filter paper with hot water before adding powder. This step is very important because if the filter paper does not fit the filter cup, it will affect the water flow speed. In addition, the filter paper and the residual taste on the filter cup can be removed through the soaking part. The second is steaming. The so-called stuffy steaming is to add a small amount of water to wet the coffee powder, and then let it stand for 20-30 seconds. This process can fully awaken the coffee powder, release some gases that affect the taste, and prepare the coffee powder for brewing. As for the way of water injection, there are round circles, back and forth, continuous brewing and sub brewing. I think it’s good to use the way I’m most used to without mistakes.

Pictures from the Internet

4. Coffee flavor

I think there are three basic flavors of coffee: bitter, sour and thick. As mentioned earlier, the proportion of acid and bitter can be controlled by selecting different coffee beans and different brewing methods. The thick thickness of coffee is actually the coffee content in the water released from the coffee powder. We will obviously feel that espresso is viscous while hand brewed coffee is clear. In addition to the coffee beans themselves, the thickness of coffee is affected by whether the extraction method is pressurized and whether paper, an absorbent filtering tool, is used.

If you can make a cup of coffee that meets your preferences, it’s even an introduction to coffee. Of course, there are more and more complex flavors in coffee, which need to be tried constantly. A coffee flavor wheel is attached below.

Coffee flavor wheel comes from the network

Coffee researchers have refined the flavor of coffee to this extent, although not all tastes are good. I think it’s great to be able to taste or make eight flavors on the innermost ring. More complex coffee world, and then slowly taste it.

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