The basic knowledge of coffee the taste and taste of coffee

The taste of coffee beans.

Sensory evaluation of coffee aroma is divided into three stages: smell, taste and taste.

1. Coffee smell

Olfactory sense refers to the sense of the olfactory organs. Odors are smelled because receptors located in the nasal septum are stimulated by volatile chemicals, usually hydrogen, carbon, nitrogen, oxygen or sulfur. These chemicals come into contact with the body's receptors when they are forcibly inhaled as gases or expelled as water vapor when swallowed. The nasal septum can distinguish thousands of different odors, and the average person can distinguish an average of 4,000 - 6,000 odors.

During normal breathing, air does not come into direct contact with the nasal septum. Inhaling or swallowing, however, forces gas into the nasal passages through a series of nasal diaphragms, where the odorous gases remain. The olfactory region contains basal cells, podocytes, and sensory cells. There are about 10 - 20 million of these receptors in the human body.

Bitterness: mainly felt at the back of the tongue. The bitter ingredients of coffee combine with acid to increase the overall sour taste of the drink.

Stimulation: mainly sensed by the back of the tongue. The combination of acid and bitterness in the coffee reduces the bitterness of the drink.

The second step is to determine the extent to which a specific taste of coffee matches these tastes. At least there are two main tastes in deep-roasted coffee: irritation and sharpness. These two tastes can be further subdivided into four secondary flavors.

Sharp to salty change-rough (rough)

Sharp change to acid-dry (astringent)

Stimulating the change to acid-- creosote oil flavor (creosoty)

Change from stimulation to bitterness-salty taste (alkaline)

In distinguishing these four flavors, we will encounter a situation unique to deep-roasted coffee:

First, since temperature has little effect on the bitterness and acidity of coffee, the change in temperature will not change the taste of deep-roasted coffee.

Second, many of the fruit acid compounds contained in coffee beans are burned away along with sugar compounds during roasting. So in deep-roasted coffee, sour taste is rarely the main flavor.

Third, when the concentration of bitter ingredients increases, the feeling of bitterness actually weakens. This is why espresso tastes less bitter than the same coffee brewed in the traditional way.

4. Coffee acidity (acidity)

Perhaps the most incorrect and misunderstood term used to evaluate the taste of coffee is "acidity". This is a quantitative term that refers to the relative strength of the acidic components in the liquid being evaluated. Although the coffee term "sour" is related to the term "acidic" that describes taste, the two terms are not interchangeable. In fact, coffee, described as "very sour", is not very acidic.

In chemistry, "acid" is defined as a compound containing hydrogen atoms. This hydrogen atom can release protons (hydrogen ions). This compound can be measured in quantity. For food technicians, almost all drinks are sour. Their relative strength is expressed by PH. The PH value is used to express the amount of free hydrogen ions in the liquid.

Coffee contains all kinds of acids, most of which can be found in other agricultural products. These acids include amino acids, such as asparagic acid, glutamic acid and leucine; carbonic acid, such as caffeic acid, chlorogenic acid and quinic acid; and fatty acids, such as acetic acid, lactic acid, citric acid, fumaric acid, oxalic acid, phosphoric acid and tartaric acid. From the taste point of view, when the concentration of amino acids exceeds the normal value, it will produce sweetness; when the concentration of carbolic acid exceeds the normal value, it will produce bitter taste; and high concentrations of fatty acids will produce sour taste.

(1) chlorogenic acid

From the point of view of concentration, the volume proportion of stone carbonic acid in coffee water is the largest. The most ingredient in this series is chlorogenic acid. There are three main groups of chlorogenic acid in coffee: coffee tannic acid, fermented quinic acid and double coffee tannic acid. Although few people have studied the sensory properties of chlorogenic acid, studies have shown that the amount of various acids (robusta is more than Arabica) and the proportion of various acids (some acids are more concentrated in immature and overripe beans than in normally ripe beans) play a major role in people's identification with a certain type of coffee.

The chlorogenic acid series also determines the taste of freshly brewed coffee. Chlorogenic acid is very unstable. The chlorogenic acid of coffee in the coffee pot breaks down into caffeic acid and quinic acid, especially when the temperature is below 80 ℃ or above 85 ℃. After decomposition, quinic acid will immediately show obvious bitter taste, caffeic acid will show sour taste. The sour taste and bitter taste are mixed to form a sour and bitter taste and the smell of old coffee.

(2) fatty acids

Another important acid is fatty acids. Although it is not the largest, it tends to produce the largest amount of hydrogen ions. The hydrogen ion measured by pH value is related to the sour taste of coffee. From a taste point of view, fatty acids give coffee a sense of brightness and aroma. This is why coffee with high acidity (low PH 4.8-5.1) usually sells for a high price.

The order of the strength of acids in coffee is generally in this order: tartaric acid, citric acid, malic acid, lactic acid and acetic acid. In addition, acid concentration also affects other major flavors of coffee water, especially sweetness. Each acid has its own flavor, such as lemon of citric acid, butter of lactic acid, apple of malic acid and so on. But they are more likely to be sensed by smell than by taste. Acetic acid in coffee is a special case. Its appearance is generally the result of the fermentation of washed coffee. The control of fermentation is the key to the quality control of this processing method. If too much acetic acid is produced, raw beans will produce a fruity flavor. The appearance of fruity flavor means that brewed coffee has an extremely disgusting fermented taste.

(3) Organic acids

Compared with wine, there is a limited amount of acid in coffee that affects its taste. This is why the aroma of coffee is locked in the aroma of coffee. Because of the complex and changeable taste of fruit acid in the wine, the process of wine tasting is an interesting taste movement process. As there are a variety of complex and volatile components in coffee, the cup review of coffee poses a challenge to the sense of smell.

5. Taste terminology

(1) Acid (acidy)

The primary taste associated with "sweet" compounds in coffee. The combination of acid and sugar in the coffee increases the sweetness of the coffee as a whole. Washed Arabica coffee growing above 4000 feet, such as Columbia Premium Coffee, has this characteristic. Sour coffee tastes from spicy (nippy) to spicy (piquant), felt by the tip of the tongue.

(2) acrid

Secondary taste associated with "soury". When the coffee has just been inhaled into the mouth, it has a very irritating sour taste felt at the back of the tongue. As the coffee cools down, the irritating taste is replaced by the sour taste. The bitter and spicy taste is due to the fact that the percentage of acid in coffee is higher than the average. In the process of mixing salt with acid, the acid enhances the salty taste. This is the characteristic of dry-processed Brazilian Rio coffee.

(3) Alkali (alkaline)

Secondary flavor associated with "pungent". Deep-roasted coffee often has this characteristic. The back of the tongue will feel dry and scratched. Alkali and carbolic acid compounds are the cause of this taste, and they also have a not-so-uncomfortable bitter taste.

(4) dry (astringent)

Secondary flavor associated with "sharp". When I first inhaled this coffee, I felt salty and tightened on the tip of my tongue. In the process of tasting, the acid makes the coffee which is already mainly salty more salty. This is the characteristic of Indonesian dry-treated Rob coffee.

(5) basic flavor (basic tastes)

The basic taste includes sweet, sour, salty and bitter. It has the taste characteristics of sucrose, tartar, sodium chloride and quinine respectively.

(6) bitter

It belongs to one of the basic flavors. It has the taste characteristics of quinine, caffeine and some other alkaloid solutions, which can be sensed by the outline papillae at the back of the tongue.

(7) Hand

The primary taste associated with "salty" compounds. The sugar and salt in the coffee reduce the overall salinity of the coffee water. Washed Arabica coffee growing below 2000 feet usually has this characteristic. For example, the washed Arabica coffee grown in the lowlands of El Salvador is an example. The taste of light coffee ranges from "soft" to neutral, mainly from the edge of the tongue.

(8) caustic

It belongs to secondary taste and is related to "harsh". When coffee is inhaled into the mouth, the back edge of the tongue will feel burning and sour. When the coffee cools down, the burning and sour taste are replaced by a rather uncomfortable sour taste. Due to the loss or lack of sugar in raw coffee beans, bitterness takes the place of sweetness in the basic flavor mixing process. This is the characteristic of dry-processed liberica coffee.

(9) creosote creosoty

Secondary flavor associated with "pungent". It is a typical taste of deep-roasted coffee. When coffee is inhaled into the mouth, there is an obvious scratching on the back of the tongue. When coffee is drunk, it will have a strong aftertaste (aftertaste) in the mouth.

Coffee bean fiber combines pyrimidine and carbonic acid produced by dry burning to produce a burning sensation and oil smell.

(10) fine (delicate)

Secondary flavor associated with "mellow". You can feel a slight sweetness when the coffee passes through the tip of the tongue. The sugar content of coffee is combined with salt (which is highly unlikely) to produce sweetness, but this sweetness is easily destroyed by other flavors. This is a typical feature of washed Arabica coffee in Papua New Guinea.

(11) hard

Secondary taste associated with "soury". When coffee is inhaled into the mouth, there is a tingling and sour sensation on the back edge of the tongue. When the coffee cools down, these two feelings will be replaced by a stronger sour taste. When the coffee fruit is harvested or dried, once the pulp of the coffee is bruised, the sugar is converted to acid under the action of enzyme, forming a strong flavor. Brazil's Parana coffee has this characteristic.

(12) Flavor (medicinal)

Secondary taste associated with "harsh". When coffee is inhaled into the mouth, there is a sharp sour feeling on the back edge of the tongue. When the coffee cools, the taste is replaced by a chemical similar to iodine. This flavor occurs because the alkaloids in coffee increase the acidity of caffeic acid and have nothing to do with sugar. Coffee fruit tastes like this when it is infected by diseases and insect pests.

(13) Glycol (mellow)

A primary taste associated with sweet compounds. The fusion of salt and sugar in coffee increases the overall sweetness of coffee. This is the origin of the smell of glycol. Washed Arabica coffee, which grows below 4000 feet, has the most such characteristics. Arabica coffee on the Indonesian island of Sumatra is one of the representatives.

(14) mild (mild)

Secondary flavor associated with "mellow". When coffee just passes through the tip of the tongue, the tip of the tongue will feel sweet stimulation. When the coffee cools down, sweetness will replace this feeling. Sweetness occurs when high concentrations of sugar are mixed with salty compounds. Guatemala's washed Arabica coffee has this characteristic.

(15) Neutral (neutral)

Secondary taste associated with "bland". Its characteristic is that after the coffee enters the mouth, there is no obvious feeling in any part of the tongue. When the coffee is cooled and picked, both sides of the tongue obviously feel dry. "Neutral" occurs because the high concentration of salt in coffee neutralizes the sour taste of acid and the sweetness of sugar, but not enough to make the tongue feel salty. Ugandan water-washed Robst coffee has such characteristics.

(16) nippy

Secondary taste associated with "acidy". When coffee is inhaled into the mouth, the tip of the tongue has a sweet and prickly feeling. When the coffee cools down, sweetness becomes the main taste in the mouth. Because the proportion of acid is higher than the average level, and the sour taste is produced by the sour taste, it is produced in the process of mixing with stronger sugar. Costa Rican SHB coffee has this characteristic.

(17) spicy (piquant)

A secondary taste associated with "sour taste". When coffee is inhaled into the mouth, the tip of the tongue feels sweet and tingling. When the coffee cools down, sweetness will become the main taste in the mouth. Because the proportion of acid is higher than the average level, and the sour taste is produced by sweetness, this taste occurs when mixed with stronger sugar. Kenyan coffee has this characteristic.

(18) Grade I coffee taste

Acidy, mellow, winey, bland, sharp and soury. The four basic flavors are produced by the interaction of different relative intensity, which is also the basis for the classification of coffee with similar taste.

(19) rough (rough)

Secondary flavor associated with "sharp". The front edge of the tongue will obviously feel torn and grinded. The additional qualities of salty taste produce this feeling.

(20) salt

It belongs to the basic flavor. It is characterized by chloride, bromide, iodide, nitrate and sulfate solution of potassium and lithium. It is mainly felt by the fungiform papillae on the front edge of the tongue.

(21) Grade II coffee taste

One of the four basic coffee flavors is produced when the first-class coffee flavor plays a leading role.

Sour-from spicy to spicy; glycol-from soft to fine; wine taste-from pungent to sour; light-from soft to neutral; sharp-from rough to dry; sour-from stiff to bitter; the temperature of coffee affects the feeling of these flavors.

(22) sharp

The primary taste associated with the salty compounds contained in the drink. The combination of acid and salt in coffee increases the overall salinity of the drink, resulting in this flavor. Unwashed Robst coffee, such as Ivory Coast coffee in Africa, often has this flavor, and "sharp" coffee ranges from rough to dry. The smell can be felt on the edge of the tongue.

(23) soft (soft)

The taste of secondary coffee associated with "light taste". The characteristic is that except for a slight feeling of dry hair, the tongue does not feel any prominent taste. The salt concentration is high enough to neutralize the acid in the coffee, but not enough to neutralize the sugar in the coffee, so this taste occurs. Dry-processed Brazilian Santos coffee has this characteristic.

24) acid (sour)

It belongs to the basic flavor. With tartaric acid. The characteristics of citric acid and malic acid solution. It is felt by the fungal papillae on the back edge of the tongue.

(25) sour (soury)

The taste of first-class coffee associated with sour compounds. Because the mixture of salt and acid reduces the overall acidity of the drink, it will produce sour taste. Unwashed Arabica coffee grown below 2000 feet, such as Brazilian dry Arabica coffee, has such characteristics.

(26) sweet

It belongs to the basic flavor. It has the characteristics of sugar (sucrose, glucose), alcohol, ethylene glycol and some acid (amino acid) solution. It is mainly felt by the fungiform papillae at the tip of the tongue.

(27) bitter (tangy)

The taste of secondary coffee associated with "winey". There is a marked irritation and sour taste along the front edge of the tongue. This taste occurs because the sugar content is higher than the average level, so the drink has a fruity taste. The "berry coffee" grown in the highlands of India has this characteristic.

(28) acid thorn (tart)

The taste of secondary coffee associated with "winey". There is a marked tingling and sour taste along the front edge of the tongue. The smell is produced because the calculated content is higher than the average level, resulting in a feeling of almost being squeezed. The sweet Arabica coffee produced in Kivu, Congo, has this characteristic.

(29) Wine taste (winey)

The first-class taste of coffee associated with taste-producing compounds in coffee. This taste occurs because the combination of sugar and acid in the coffee reduces the overall sour taste of the coffee. Unwashed Arabica coffee grown above 4000 feet, such as Ethiopia's Djimma coffee, has this characteristic.

10. Coffee taste

Taste refers to the feeling in the mouth during or after the intake of food or drink. The concentration, viscosity and surface tension of the sampled samples, as well as the physical and chemical characteristics of other components, cause this series of sensations in the outlet. The soft tissue in the mouth has a free nerve endings system, as well as closed and unclosed nerve centers that respond to contact, light pressure, and thermal, chemical and mechanical stimuli.

The "sensory" characteristics of food or beverages are usually one of the most important aspects of their quality. Measuring their hardness, softness, juiciness and oiliness with their mouths is as good as measuring them with their fingers. Whether the food or drink can continuously release the taste during the feeling process is very important both physically and psychologically. If the food or drink disappears or is consumed before it is ingested, people will have an impulse to refuse to eat or drink the food or drink.

I. Coffee ingredients

For coffee, the touch of the mouth and palate comes from water-insoluble liquid components-fatty oils, and water-insoluble solids-sediments suspended in coffee water after brewing. In addition to providing texture for the overall taste of coffee, suspended matter in coffee also affects the taste of coffee by forming colloids.