Why does Pu 'er tea have osmanthus fragrance?

This is the most commonly used aroma description of Pu 'er tea (raw tea) and sun-cured green tea. Because of its fresh and indifferent meaning, it is completely different from the rich fragrance, which makes people smell elegant, such as the breath of deep mountains and forests and vast grasslands, but natural, harmonious and comfortable. But don't put your nose on the grass on the grassland, because it is as pungent as the blue smell from the lawn mower passing by in the park. The natural aroma of tea is also a matter of concentration to a great extent.

The molecular composition of tea fragrance is mainly celadon and some simple aliphatic molecules. Cis-geraniol smells like grass at high concentration, smells like grass at low concentration, and trans-geraniol smells like grass directly. Cis-geraniol can be converted into trans-geraniol by isomerization during processing. In the early stage of water fixation, with the increase of leaf temperature, homeopathic geraniol volatilized and converted into trans geraniol, and some simple aliphatic molecules produced by high temperature pyrolysis formed the characteristics of aroma.

2. Incense

Aroma characteristics of Pu 'er tea when it is high-grade. As the name implies, it is the fragrance of "milli". Contrary to "coarse", this fresh and tender bud has a unique fragrance, which makes people feel more fresh and pleasant. "Xiang Xiang" can also be described as "tender fragrance", which is a softer and more lively fragrance.

Miho describes the overall performance of mixed aroma, so there are many aroma substances involved. Because of the higher grade of raw materials, the content of most effective aroma substances is relatively high, and the aroma substances with higher concentration may be slightly different from the general tea aroma.

3. Fresh floral fragrance

The fragrance of flowers is very common in Pu 'er tea (raw tea), which is expressed in various ways, and the fresh and fragrant characteristics of many teas are often impressive. This type of floral fragrance, such as lily of the valley or lily, is pure, just a pure sense of smell, unlike fruity honey, although it can be very fragrant, fragrant through the wall and refreshing. "Fresh floral fragrance" can also be called "high floral fragrance".

Linalool is a kind of aroma substance with high boiling point, and it is the most important contribution to the fresh and refreshing fragrance of raw tea. The low-boiling aroma substances, represented by green leaf alcohol, show the floral fragrance of lily or lily of the valley after enzyme solid volatilization. No matter the grade of tea, the variety of tea tree, the environment of tea garden and the picking season are closely related to the content of linalool, which directly or indirectly leads to the different aroma characteristics of different varieties in different grades, seasons and regions.

4. Sweet and mellow floral fragrance

This kind of fragrance, such as jasmine or gardenia, smells very pleasant and often makes people take a deep breath unconsciously, making their spirits more comfortable. The so-called cup of fragrant tea can wash away confusion, but the fragrance must be delicate. Otherwise, like a rose, it will inevitably make people intoxicated. If it is like a orchid, it will lead to carelessness. Fortunately, there is a sweet and mellow breath that can shake people's hearts, which is most beneficial when the afternoon nap demon strikes.

This kind of aroma is very common in raw tea, and aroma substances such as β-ionone, jasmonate ester and some ionone derivatives are all involved in the performance of this aroma type in raw tea. These aroma substances are basically produced in the process of processing, and different boiling points, different contents and proportions will produce different effects, which is one of the reasons for the diverse aroma characteristics of Pu 'er tea.

5. Soft floral fragrance

This fragrance is represented by rose fragrance, and some raw teas stored for several years will show this fragrance. This soft aroma in Pu 'er tea (raw tea) is different from the smell-stimulating aroma of fresh alcohol or sweet alcohol, which makes people feel tepid and rare in Pu 'er tea. The so-called "spearmint type" can also belong to this category, but spearmint is deeper and softer than rose fragrance, and it is close to the state of being absent.

Aroma molecules related to rose aroma are mainly geraniol, which has rose aroma and is an important aroma substance in tea. The higher the grade, the higher the tea content. But generally speaking, the geraniol content of Yunnan big leaf species is lower than that of middle leaf species, so there are few Pu 'er teas that can show rose fragrance. There are many molecules related to spearmint. When floral molecules wander on the threshold of smell, they may all show occasional spearmint.

6. Sugar flavor

Sugar fragrance is also very common in Pu 'er tea, among which rock sugar fragrance is the most prominent, often accompanied by strong sweetness and cool throat feeling, so it is a characteristic of excellent tea quality. And people who smell like sugar cane have their own style.

On the one hand, the aroma components of sugar have some similarities with the sweetness of honey, on the other hand, it is the aroma of some sugar itself. The soluble sugar content in Pu 'er tea is very high, generally accounting for 4-7% of dry matter.

However, the sugar aroma mentioned here is a positive aroma type that makes a positive judgment on the quality of Pu 'er tea, excluding the caramel aroma that will be introduced below.

7. caramel fragrance

This is often a feature when Pu 'er tea processing is irrelevant, and the chocolate fragrance that has attracted much attention also belongs to this category. This aroma gives a sweet feeling in baked goods such as toast and biscuits, which is very important and positive in the food industry. However, it is counterproductive to put it in Pu 'er tea. It means that tea leaves are baked or fried at high temperature, which leads to the decline of tea activity, and some substances closely related to the later transformation, such as residual enzymes, will be killed in large quantities, which seriously hurts the characteristic quality of Pu 'er tea. So from this point of view, this caramel scented tea is not suitable for long-term storage. The view that baked green is not suitable for storage can be found in Zou Jiaju's Dry Glycol (Zou Jiaju's Random Talk on Pu 'er Tea). In the experimental research, there is no systematic demonstration, but the national standard recognizes this view, and it is limited that Gan Qing, a big leaf species in Yunnan, must be used as raw material. Nowadays, both academia and market acquiesce in this view.

The caramel aroma is caused by caramelization reaction of saccharides at high temperature, thus producing caramel aroma. (ortho-substituted pyrazine has obvious chocolate taste)

8. Fruit fragrance

This aroma is ubiquitous in Pu 'er tea, such as apples, lemons, sweet peaches, watermelons and so on. The reasons for the formation are different, some are because aroma substances with fruit fragrance can appear, and some are because of the effect of mixing several fragrances, so although common, they are elusive. For example, apple fragrance is common in fresh tea, watermelon fragrance is common in raw tea which has been stored for a long time, but it is more fruity tea, such as antelope hanging horns, which is elusive.

Related aromas include some ionone derivatives, some lactones with strong sweetness and fruit flavor, some terpene esters with lemon flavor, and linalool oxide produced during processing and storage.

9. Plum fragrance

Plum fragrance often appears in raw tea stored for a certain period of time, which is a very good classic aroma in Pu 'er tea. Mei Xiang, the most representative, smells cool and slightly sour, just like plum, and is widely praised. Why is Mei Xiang so cute? The main reason is a psychological effect, that is, the contrast effect. (In cognitive psychology, the phenomenon that a specific feeling is affected by different or opposite stimuli at the same time or successively is called contrast effect. ) When we add a little bit of other different fragrance types to a single fragrance type, both fragrance types will be more prominent, and the contrast effect in plum fragrance is very typical.

Some teas are often attached with plum fragrance because of improper fermentation or improper storage, but there is a big difference between them. Mei Xiang is natural and comfortable, and there is no sense of disobedience with tea, but the sour gas is abrupt. The tea with plum fragrance tastes pure, while the tea soup with bad acidity tastes sour.

The reason why the two are different is the degree. No matter natural fermentation or artificial fermentation, some fatty acids, such as valeric acid and decanoic acid, will be produced. If the fermentation is improper, these acids will accumulate in large quantities, resulting in abrupt sour taste, which will affect the taste and aroma. However, if it is controlled in a proper range, it will not affect the quality, and even form a good fragrance similar to plum fragrance.

10, dried fruit flavor

This aroma is rare in Pu 'er tea, such as bitter almond, pine nuts, betel nut and so on. Pu 'er tea with dry fruit fragrance is often stored with raw tea and some mature tea with high aging degree for quite many years.

The directly related aroma substances are benzaldehyde with bitter almond flavor and tea spironolone and 2- ethoxythiazole with dried fruit flavor.

1 1, honey fragrance

Honey fragrance is common in Pu 'er tea (raw tea). Tea leaves in many tea areas can present honey fragrance for a long time during storage, and this fragrance is durable and easy to describe and understand, so it is easy to remember. The quality of honey-scented Pu 'er tea is also good. Sometimes drinking pure tea with honey fragrance can leave a full-day aftertaste in your mouth. The combination of honey fragrance and floral fragrance constitutes the remarkable characteristics of most Pu 'er tea (raw tea) in the early stage of aging.

The main aroma component of honey fragrance is phenylmethyl phenylacetate, which has a high boiling point, so it dissipates slowly and can exist for a long time. In addition, benzyl alcohol also has a faint honey sweetness, which also contributes to a strong fragrance.

12, Sean

Chen Xiang is common in Pu 'er tea (cooked tea) and Pu 'er tea (raw tea). After long-term storage, the degree of transformation close to maturity is very high. Chen Xiang is the core aroma type of Pu 'er tea (cooked tea), and pure Chen Xiang is the representative aroma type of Pu 'er tea (cooked tea). Other fragrance types are discussed on the basis of aging fragrance. Without Chen Xiang, Pu 'er tea (cooked tea) is unqualified.

Chen Xiang smells similar to the fragrance of old wooden furniture, but it is more energetic. Different from the dull old taste of other teas for a long time, Pu 'er tea should have an old fragrance, which is old and active, without a dull feeling. "Activity" is the tasting node of Pu 'er tea, and it is also the consistent core element in the whole Pu 'er tea appreciation.

Aged aroma is a complex mixed aroma, which is a mixed expression of aged flavor, woody aroma and medicinal aroma. There are many aroma substances involved, among which 1, 2- dimethoxybenzene, 1, 2,3-trimethoxybenzene and 4- ethyl-1, 2- dimethyl have the greatest contribution to the aged aroma of Pu 'er tea.

13, jujube fragrance

This aroma smells like dried dates, some sweet and some woody, which is generally the characteristic of cooked tea. Jujube fragrance is a very classic style in Pu 'er tea.

This kind of fragrance is often easy to appear in Pu 'er tea with coarse and old raw materials, because coarse and old leaves generally have high sugar content and can produce more soluble sugar during fermentation. When the aroma of sugar reaches a certain level, it can be mixed with other aromas such as radix aucklandiae, showing the aroma similar to that of dried dates.

14, longan fragrance

This aroma smells like dried longan, which usually appears in high-grade Pu 'er tea (cooked tea). Longan fragrant Pu 'er tea often has a high degree of fermentation and a high drying temperature during processing.

Longan in Pu 'er tea is similar to jujube, but it is often not as mellow as jujube.

Zhangxiang 15

Cinnamomum camphora mostly appears in raw tea which has been stored for a long time. It smells like camphor wood and has a quiet and natural feeling, which is different from camphor. Some moldy and deteriorated tea leaves will have a pungent camphor smell similar to pesticides.

The main aroma substances related to Cinnamomum camphora are camphene and fenpyrone, both of which are camphor-flavored aroma components. When mixed with flowers and trees, Cinnamomum camphora is pleasant.

16, radix aucklandiae

Aucklandia is a very common aroma in Pu 'er tea, especially in cooked tea. Pu 'er tea (cooked tea) processed by some selective microbial inoculation techniques will have a very prominent woody root. Aucklandia is different from flowers and honey, giving people a low and gentle feeling, which is beneficial to the quality of Pu 'er tea.

The components that make the greatest contribution to the Radix Aucklandiae of Pu 'er tea are α-ionone, β-ionone, α-cedrol, α-cedrene, β-guaiacene, dihydroactinidiolide and so on.

17, moldy

Moldy tea leaves produce a pungent and unpleasant smell. It usually exists in improperly stored tea leaves, such as tea leaves that deteriorate after long-term storage in high temperature and high humidity environment.

The main substance related to the musty smell in Pu 'er tea is 3,4-dimethoxytoluene.

18, Shenxiang

Aroma similar to ginseng, common in cooked tea stored in high temperature and high humidity environment.

The aroma components in Pu 'er tea are similar to ginseng, such as palmitic acid with earthy smell and acacia with woody smell. In addition to these substances, the ginseng aroma characteristics of Pu 'er tea also include some woody aroma and sweet aroma.

19, smoke smell

Smoked taste is not the original taste of tea, but is impregnated during processing or storage. It is a common smell in tea and has no positive effect on the quality of Pu 'er tea.

Because of the characteristics of sun-dried green tea, it is often necessary to move the tea indoors to dry in the rainy season to avoid rain and be easily infected by farmhouse music in mountainous areas. Therefore, summer and autumn tea is more likely to smell like smoke.

There are many substances related to smoke smell, among which guaiacol and 4- methyl guaiacol are the most important. These substances have high boiling point and slow dissipation, so it is difficult to dissipate the smell of smoke by storage.

20. The smell of smoke is burnt.

The burnt smell of smoke is a common bad smell in Pu 'er tea. The reason is that the deactivation temperature is too high and some leaves are burnt. Therefore, the smell of smoke and coke often appears in Pu 'er tea, and the processing is very rough.

2 1, Yaoxiang

The fragrance of medicine is naturally the breath of traditional Chinese medicine. For example, the smell of traditional Chinese medicine that people in pharmacies smell is actually the smell of vegetation in Chen Fangjiu, because tea is also vegetation, and a similar smell will naturally appear in Chen Fangjiu.

Tea leaves age faster in the hot and humid climate in the south, and may feel medicinal fragrance after a few years, but it is difficult to have medicinal fragrance for a long time when stored in a dry climate.

The related aroma substances of medicinal incense are mainly decanal, saffron aldehyde and various components related to Radix Aucklandiae.

22, sauerkraut gas

In the newly-made raw tea, there is often a sour smell similar to sauerkraut. People who collect tea in Chashan often see that the production equipment of tea farmers is crude, and sometimes pigsty can be seen next to the warehouse, so they think of pig urine gas and the like. In fact, sauerkraut gas is caused by the processing technology of sun-cured green tea, and it is by no means pollution.

When making tea in many old factories, the processing master will stack the tea leaves for a period of time after fixing them. With this process, the color of tea leaves will be deeper, the taste will be more mellow, and the aroma will be different after drying, but if the tea leaves are covered a little more, they will have a taste similar to sauerkraut. In every tea mountain, especially those famous tea villages where every household makes tea by hand, it can be found that individual workshops have this kind of tea-making technology, which is even considered as a secret that is inconvenient to spread.

The substances related to this odor are mainly low-grade fatty acids, which are easy to volatilize and escape, so it has little effect on the quality of Pu 'er tea which is planned to be stored for a long time.

23. Wild mushroom fragrance

The aroma of wild mushrooms generally appears in Pu 'er tea (raw tea), which is attractive and appetizing and can arouse people's desire for tea. It is a very classic aroma, and the aroma of wild mushrooms is often accompanied by advanced quality.

Its aroma components are mainly a series of eight-carbon flavor compounds converted from linoleic acid, such as 1- octene -3- one, 1- octene -3- alcohol and so on. These substances have low boiling point and disperse quickly, so it is not easy for tea with long shelf life to retain the fragrance of wild mushrooms.

24. Bake and stir fry

Sometimes it appears in improperly made Pu 'er tea (raw tea), which is an aroma that should be avoided as much as possible.

For example, chestnuts and beans are all roasted and fried, which is the smell formed by thermochemical action. It belongs to the positive aroma type in many foods and other teas, but the quality characteristics of Pu 'er tea determine that it is not suitable for high temperature, so the appearance of baking aroma should be reduced in the quality evaluation of Pu 'er tea.

The chemical composition of roasted incense is mainly heterocyclic compounds containing sulfur and nitrogen, which can only be produced by high temperature processing.

25. Right taste

Heap smell comes from the description of "fermentation pile", which describes a kind of fermentation smell similar to mixed acid, rancidity, mildew, fishy smell and other bad feelings.

It is common in newly cooked tea, because the fermentation process of traditional cooked tea is a long and complicated process, and it is impossible to achieve absolute uniformity when several tons to dozens of tons of tea are fermented together, so some over-fermented and under-fermented tea will produce some odor. How to minimize this odor when processing is completed is a test of processing technology.

If there is no serious under-fermentation or over-fermentation, then these unfriendly smells can be naturally separated and displayed by reasonable storage for different time periods according to the concentration of the smell.

26, water stew gas

Pu 'er tea (raw tea) which is often stewed with rain leaves or twisted leaves and not dried in time.

Just like the smell produced when cooking with a pot cover, a similar smell will be produced if there is damp heat and air tightness in the small environment where tea is processed.

27. Green gas

Commonly found in Pu 'er tea (raw tea), it is not enough to kill green, and it smells like grass. Because the contents of fresh leaves lack the necessary transformation.

Its principle can refer to fragrance.

28, coarse green gas

It is commonly found in Pu 'er tea (raw tea) with coarse and old raw materials, and has a grassy smell. Because the fresh leaves are coarse and old, and the water content is low, it is necessary to "kill the old leaves tender" in the process of de-enzyming, that is, the de-enzyming time is short and the de-enzyming temperature is low, so it is difficult to ensure the loss of related green gas substances such as green leaf alcohol, so there is often coarse green gas.

29. Sun Wenzhi

It usually exists in fresh Pu 'er tea (raw tea) which has been stored for a short time. This smells like a quilt that has been dried on a sunny day.

Light can promote the oxidation of esters and other substances, among which ultraviolet light has a greater influence than visible light. Long-term light will cause photochemical reactions of tea chemicals. It can be guessed that a series of related odor substances produced by photochemical reaction are isomorphic with the smell of the sun, but their specific components remain to be studied.