What are the fermentation methods of raw coffee beans? What is the bad flavor of overfermentation of raw coffee beans?

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What are the processing methods of coffee bean fermentation? What is the bad flavor of overfermented coffee beans?

Coffee beans are not born as dark brown beans. Coffee fruit is shaped like red dates fruit, each fruit has 2 coffee beans, coffee fruit, coffee beans after processing, will be what we usually see. Coffee production includes harvesting, processing, peeling, picking beans, roasting, storage, grinding, brewing and other processes, of which "processing" is one of the initial keys to affecting coffee flavor. Generally, when coffee beans are fermented, coffee beans will be soaked in water for fermentation, whether static water or flowing water.

For many years, it has been introduced that it is best not to soak in water for so-called fermentation, that is,"anhydrous fermentation" or "dry fermentation". It makes it easy to make high-quality coffee.

Even when peeling from coffee, there is no need to inject water to increase the moisture of coffee fruits, helping the peeling operation. When making coffee peeling machine, especially strengthen the anhydrous peeling function.

Why do you say anhydrous fermentation? Because the colloid of coffee fruit is a sugar substance, it is the main substance of fermentation. As long as the water comes into contact with the whole process, the colloid will be washed away, which will reduce the fermentation effect.

Unfortunately, there are still not many recipients. Those who didn't understand continued to pretend that they didn't understand.

There are many ways to treat coffee beans, and the treatment methods will affect the aroma of coffee. The following two common methods of solarization and washing are described:

1, sun exposure method: coffee fruit picked, pick immature fruit and miscellaneous leaves, direct exposure to the sun coffee fruit 2- 3 weeks, dry after removing the shell, because pectin is still attached to the outside, so it will have pectin taste. The degree of solarization varies depending on the temperature and humidity of the dry environment. Lin Zhehao said that Brazil's southern Minas region belongs to the tropical savanna climate zone, with strong sun exposure, low fermentation degree and more nutty flavor; Latin America is not, most processes are highly fermented, full of fruit and wine fragrance. In addition, the use of mechanical drying of whole fruit drying is also known as solarization.

2. Washing method: The key point is that the coffee fruit is fermented after peeling, and the pectin is washed away with water after fermentation. One of the methods used is to remove the immature fruit and miscellaneous leaves after picking the coffee berries, remove the skin of the fruit, pick out the beans, then wash and soak the beans, so that the beans begin to ferment, allowing microorganisms and enzymes to decompose the ingredients of the beans, producing sour flavor. Water washing method can also be adopted dry fermentation method, without soaking, fermentation and then water to wash away the pectin. Fermented beans, and then to sun or drying coffee beans to avoid mildew. Coffee beans that are properly washed usually taste milder, and depending on the environment and fermentation conditions, may also have a fragrant flavor.

After processing coffee beans, first pick out defective beans, leave intact coffee beans, and then through different degrees of roasting, finally can have a variety of flavors and tastes. The subtle differences in each step from production to brewing affect the quality and flavor of coffee, which is why the world of coffee is so spiritual and fascinating.

The first stage occurs during harvesting and drying.

When farmers dry coffee fruits or beans, it will affect the aroma of coffee beans, and in serious cases, it will cause rancid smell.

If the fruit is left in the coffee garden too long at harvest time, the bad smell will continue to be produced, and the enzymes inside the fruit will start to break down the substances inside the seeds.

Because of chemical changes, arabica beans produce a "rioy" smell and robusta a "rubbery" smell.

Rubbery

In the drying stage, if the coffee fruit is placed in a high temperature and humid environment, the internal enzyme action accelerates and produces a "fermented flavor".

(Note: This is why it is repeatedly emphasized that the peeling of coffee fruits should be completed on the same day after harvest, or within 24 hours, and should not be stacked for too long.)

fermented

Generally, coffee beans are spread on the concrete floor, or on a high drying bed, or on a plastic cloth.

The main thing is to keep the place clean and clean and avoid pollution. If coffee beans are kept in an unclean place, especially on a dry dirt floor, the oil inside the beans absorbs the smell of the soil and produces an "earthy" smell.

earthy

If the coffee beans are placed in wet places, it is easy to cause mildew and produce a "musty smell". If mechanically dried, the drying speed is too fast, the oil inside the beans is decomposed, resulting in a "skin odor"(hidy).

Skin smell hidy

(Note: It feels like mold is happening slowly.) In fact, because of the humid environment or rain, the speed of coffee beans moldy is very fast, about 1-2 days, you can see the appearance of moldy phenomenon. In fact, when you see this moldy appearance, it has been moldy for some time.)

The second stage occurs during storage and is the aging of coffee beans.

This is the period from harvest and drying to baking.

In the first few months after harvest and processing, coffee beans have a distinctive grassy smell, like freshly harvested alfalfa, known as "grassy." grassy

The enzymes in the raw beans continue to function, and after a few months, this aroma characteristic gradually decreases. Until shipped for sale, they are called "new crop," meaning "beans in season."

(Note: Fresh beans that have just been harvested and produced have their own characteristics and also have their inevitable smell. This is why foreign beans are not in a hurry to ship after harvesting and post-processing. It is to reduce the smell.)

Coffee beans under proper storage conditions will reduce the speed of enzyme action.

After about a year, these chemical changes begin to affect the acids inside the beans. Taste senses this change, and the coffee beans are already "past crop." If the green beans are stored for several years, the enzyme action greatly reduces the content of various acids, this coffee bean is called "old beans or aged beans"(aged).

In addition to enzyme action, coffee beans slowly lose organic matter and gradually develop a hay-like "strawy" flavor.

strawy

After a few years, coffee beans continue to lose organic matter and eventually produce an unacceptable "woody" taste.