What is coffee roasting? How does the coffee change after roasting? Trends in coffee roasting in various countries?

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Basic concept

Raw coffee beans themselves do not have any aroma of coffee, only after fried, can you smell the strong aroma of coffee. So the roasting of coffee beans is the transformation process of the internal components of coffee beans, only after roasting to produce ingredients that can release the aroma of coffee, we can smell the aroma of coffee. But in the roasting process of coffee beans, the transformation of ingredients is very complex, after all, coffee beans are organic matter, so the transformation of this component is very complex, and the modern knowledge of organic chemistry can not fully understand.

However, the roasting of coffee beans directly determines the aroma of coffee beans. Coffee that is not roasted well cannot be obtained even if raw coffee beans are good. Very good coffee and ripe beans; as a result, of course, you can't make good coffee. Only with good coffee raw beans, after proper roasting, it is possible to process good coffee cooked beans, and it is also possible to provide a good prerequisite for making good coffee.

Fried coffee beans are roasted at high temperatures, or roasted, to create the coffee's unique color (similar to amber, depending on the degree of roasting), flavor and aroma. Frying turns the green (or yellowish) raw coffee beans into the familiar tea-brown coffee beans. High-quality fried roasting refers to the ingenious expression of the aroma, sour and bitter ingredients of raw coffee beans.

Technical Research

A series of chemical changes occur in the process of baking. After about 5-25 minutes of baking (depending on the temperature selected), the green coffee beans lose some humidity and turn yellow. In this process, the coffee beans will swell, changing from a strong, high-density raw bean to a low-density fluffy state. After this process, the coffee beans will about double in size and begin to show a light brown after stir-frying. After this stage is completed (after about 8 minutes of baking), the calories will be reduced. The color of the coffee soon changed to dark. When the preset baking depth is reached, cold air can be used to cool the coffee beans in order to stop the baking process.

Baking is roughly divided into shallow baking (Light), medium baking (Medium), urban baking (City) and deep baking (Deep). Light roasted coffee beans: will have a strong smell, very crisp, high acidity is the main flavor and slightly mellow. Medium-roasted coffee beans: have a strong mellow, but also retain a certain degree of acidity. City-baked coffee beans: the surface is dark brown, the acidity is replaced by slight bitterness, and most of the flavor has been destroyed. Deep-roasted coffee beans: dark brown in color and oily on the surface. For most coffee beans, the alcohol content increases significantly and the acidity decreases. In fact, roasting coffee is a way of processing food. The roasting of professional coffee is the personal expression of the roaster. The biggest problem when you first come into contact with professional coffee beans with different roasting degrees (SPCIAITYCOFFEE) is the name of the roasting degree. For example, CITY, FUIICITY, FRENCH, ESPRESSO, etc., all produce different baking colors because of the different baking machines and producing areas. In addition, some roasting levels are named after mixed coffee: for example, ESPRESSO is a coffee with a specific roasting degree for making ESPRESSO, and even if the color looks the same, it may have a completely different flavor. Therefore, the selection of the type of beans, baking temperature and baking method, and the length of baking time are the main factors that determine the final flavor.

Baking stage

The roasting method of professional coffee is usually divided into the following eight stages.

1. Very shallow baking (LIGHTRoast):

The degree of baking; very shallow baking, also known as shallow baking.

The lightest roasting degree of all roasting stages, the surface of the coffee beans is a light cinnamon color, its taste and aroma are insufficient, this state is almost undrinkable. It is generally used for testing and seldom for tasting.

2. Shallow baking (CINNAMONRoast):

Degree of baking; shallow baking, also known as cinnamon baking.

The general baking degree, showing cinnamon color on the appearance, the smell of green has been removed, the aroma is OK, and the acidity is strong, which is a common roasting degree of American coffee.

3. Micro baking (MEDIUMRoast):

Baking degree; moderate baking, also known as micro baking.

Medium baking heat and light baking are both American, in addition to sour taste, bitterness also appears, the taste is good. It has moderate aroma, acidity and mellowness, and is often used in the baking of mixed coffee.

4. Medium baking (HIGHRoast):

Baking degree; moderate micro-deep baking, also known as concentration baking.

Belongs to the moderate micro-deep baking, the baking degree is slightly stronger than the slight medium baking, the surface has appeared a little thick brown, the bitterness also becomes stronger. Coffee tastes sour and bitter, with good aroma and flavor, and is most often loved by people in Japan and Central Europe. (blue Mountain Coffee)

5. Medium and deep baking (CITYRoast):

Baking degree; medium-deep baking, also known as urban baking.

The most standard degree of roasting, bitterness and acidity are balanced and are often used in French coffee. (Brazil, Colombia)

6. Deep baking (FULL-CITYRoast):

Baking degree; micro-depth baking, also known as deep city baking.

The baking degree is slightly stronger than the medium depth, the color becomes quite dark, and the bitter taste is stronger than the sour taste. It belongs to the Central and South American baking method, which is very suitable for preparing all kinds of iced coffee.

7. Very Deep Baking (FrenchRoast):

Degree of baking; deep baking, also known as French baking.

Also known as French or European baking, belongs to deep baking, the color is thick brown with black, sour taste can not be felt, especially in Europe, France is the most popular, because the fat has infiltrated to the surface, with a unique flavor, very suitable for coffee Oulei, Viennese coffee.

8. Very Deep Baking (ItalianRoast):

Degree of baking; very deep baking, also known as Italian baking.

Also known as Italian baking, baking degree before carbonization, there is a scorched taste, mainly popular in Latin countries, suitable for fast coffee and cappuccino. Most of them are used in Espresso coffee series.

Coffee roasting

Baking depth meter

Baking depth appearance baking stage (the following temperature data are for reference only because of the different positions of temperature control points in different roasters)

Very shallow baking LIGHT

Light brown

Before and after the first explosion, 195 to 205 degrees

Shallow baking CINNAMON

Yellowish brown

The first explosion is over, about 205 degrees.

Medium baking / micro baking MEDIUM

Brown

About 205 to 215 degrees

Medium and deep baking / city baking, CITY

Reddish brown

About 215 to 225 degrees

City-wide baking, FULLCITY

Dark brown * dotted oil

About 225 degrees 230 degrees before the start of the second explosion

French baked French

Dark brown * oily on the surface

About 230 to 235 degrees

Italian baking is deep baking, Italian

ESPRESSO baking

Close to the black surface and greasy

Above 240 degrees

National tendency

Cities all over the world have their preferred baking tendency.

In Tokyo, micro-deep medium baking is more popular, but slowly it also tends to deep baking. As for Kansai, deep baking has been popular in the past.

New York, as its name suggests, generally prefers urban baking, but because the city is inhabited by different races of people, it also sells coffee beans with different roasting degrees, and the variety is also quite rich.

Vienna prefers deep baking. Even as the name suggests, the French prefer French baking, while Italians often use Italian baking.

However, in recent years, Italian baking (the most commonly used deep roasting in Brazil and Italy) has been widely used in Europe and the United States, and the coffee made by steam pressurizer is still popular.

Deep roasting of Ethiopian coffee beans would be a waste. Because that would lose the unique characteristics of this coffee. Black roasting of Yauco and Kona coffee beans is also bad, because you will lose the classical flavor you pursue when you buy it.

When some coffee beans are roasted black, new and interesting qualities will be derived. Mexican coffee beans produce an interesting sweetness when roasted in black.

Guatemala Antigua coffee beans seem to retain their sour and fruity flavor when they are deeply roasted, which is difficult for other coffees.

Sumatran coffee beans are usually full-grained, but are below medium acidity, lose acidity when roasted deeper, and easily turn into sugar paste.

Generally speaking, the darker the baking, the lower the quality. Deeper roasting means losing most of the flavor of the coffee beans.