The chemical composition of liquor is 98% water and ethanol, and 65,438+0% ~ 2% trace components (alcohols, esters, acids and aldehydes and ketones) with flavor and taste, among which trace components determine the flavor and style of liquor.

Liquor blending is the root of the whole liquor production process. Aroma production depends on fermentation, and aroma blending depends on blending. It is aimed at the traditional liquor technology. Traditional liquor blending method is a means to ensure product consistency and liquor coordination. Wines from different years, different cellars and different flavors are blended with each other to achieve the purpose of coordinated flavor, outstanding style and unified product quality. The blending of new-type liquor is often the blending of alcohol, purified water, mixed liquor, solid liquor and flavors and fragrances, thus making this kind of product a new-type liquor with uniform quality, harmonious flavor and outstanding style.

Good white wine has a tangy smell. Many aroma components have been identified in liquor. At present, there are 136 kinds of aroma components in China liquor (90 kinds are quantitative), including 25 kinds of acids, 42 kinds of esters, 30 kinds of alcohols, 4 kinds of aldehydes 10, 4 kinds of polyols, 4 kinds of sulfides and 4 kinds of free ammonia, and the total number of some unidentified components exceeds 150. According to foreign reports, the aroma components in alcoholic beverages are composed of hundreds of different compounds, including 28 alcohols, 80 acids, 1 18 esters and 4 1 carbonyl compounds. Acetal 17, phenol 4 1, hydrocarbon1,nitride 18, sulfide 1 1, lactone 17, saccharide 4 and inseparable compounds.

The content of these aroma components in liquor is very small, but in a proper proportion, liquor has a beautiful and special aroma. The aroma characteristics of various wines are the balanced expression of their aroma components. No matter how complex the aroma components in liquor are, there is always a main aroma and additional aroma components in every type and style of liquor, which together constitute the typical aroma of liquor. The sensory quality of liquor aroma should be harmonious aroma, pleasant feeling and prominent main aroma. At the same time, consider its fragrance, fragrance and fragrance retention. Good-smelling wine (that is, good-smelling wine) is fragrant and fragrant when poured out, indicating that the wine has more aroma. Wine with good aroma (that is, wine with good aroma at the entrance) overflows in the mouth as soon as it enters, indicating that the wine contains many low-boiling aroma substances. The wine with good aroma retention (that is, the wine with good aftertaste) still has a lingering fragrance after swallowing, and it also has a particularly comfortable aroma after drinking burps, indicating that its ester content is more, especially the high-boiling aroma substances. These aromatic components are esters, acids, alcohols and carbonyl compounds.

(1) Esters: There are the most aromatic substances in liquor, and esters have the greatest influence. Esters are volatile compounds with aromatic smell, which are the main substances that constitute the aroma of wine, and play a decisive and key role in the formation of various wine typical bodies.

The average ester content of high-quality liquor, Luzhou-flavor liquor or famous liquor is 0.2 ~ 0.6%, that of Daqu liquor is 0.2 ~ 0.3%, and that of ordinary liquor is below 0. 1%, but the total ester content must be not lower than 0.05 ~ 0.08%.

Liquor generally contains ethyl formate, ethyl acetate, isoamyl acetate, ethyl propionate, ethyl butyrate, ethyl valerate, ethyl caproate, ethyl heptanoate, ethyl octanoate, ethyl decanoate, ethyl laurate and ethyl lactate. Esters in liquor are mainly C 1 ~ C 14 linear fatty acid esters. The fatty acid esters with 1 ~ 2 carbon have weak aroma and short duration. Esters of 3 ~ 5 carbon fatty acids have a fatty smell, so the content of wine should not be too much; Fatty acid esters with 6 ~ 12 carbon have strong aroma and last for a long time, while fatty acid esters with 12 carbon or more have almost no aroma. The main esters in liquor are ethyl acetate, ethyl caproate and ethyl lactate, and their sum accounts for more than 85% of the total esters in liquor. Therefore, it is called the three major esters. The change of ester content in the three major esters has a decisive influence on the flavor of wine. Ethyl acetate tastes like apples and bananas when it is thick, and pears and pineapples when it is thin. Ethyl caproate is spicy and smelly when it is thick, and gives liquor a special cellar flavor when it is thin. Ethyl lactate has the characteristics of no fragrance, which has a strong sweet feeling to the taste of wine and astringent taste when it is strong. In common liquor, the ratio of ethyl acetate to ethyl lactate is 2∶ 1, which is the main component representing liquor style. Especially, ethyl lactate is the main aroma of Laobaigan. Even in Luzhou-flavor liquor with ethyl caproate as the main aroma, ethyl lactate and ethyl acetate also occupy an important position. Liquor loses its own flavor without ethyl lactate, but if the content is too high, it will taste like grass and astringent. In Luzhou-flavor liquor, in addition to ethyl caproate as the main aroma component, there is another main aroma component, namely ethyl butyrate. Ethyl butyrate smells bad when it is thick, with a slight odor, and it smells like rum when it is thin. Ethyl butyrate is one of the aroma components of old pits in liquor, and its content should not be too high, otherwise it will bring fatty taste.

(2) Acid: Acid is an important flavor substance in liquor, which together with other flavor substances and * * * constitutes the unique aroma of liquor. The wine with less acid content has light taste and short flavor; If the sour taste is strong, the taste of the wine is rough. Proper amount of acid can play a buffering role in wine, which can eliminate the disharmony of taste after drinking. Acidity can also promote the sweetness of wine, but the sweetness of excessively acidic wine is reduced, which also affects the taste. Generally, the acid content of high-quality liquor is high, which is about twice as high as that of ordinary liquor and twice as high as that of ordinary liquid liquor. Insufficient acid content will make wine lack the inherent flavor of liquor, but too much acid will cause bad smell and reduce the quality of liquor, so some provinces stipulate that the maximum acid content in liquor should not exceed 0. 1%. But the acid content of general liquor should be about 0. 1 g/ 100 ml. The main components of acid in wine are acetic acid, caproic acid, lactic acid and butyric acid, and their sum accounts for 90 ~ 98% of the total acid. At the same time, the proportion of different wines is also different. For example, the content of acetic acid is the highest in the total acid of Fen-flavor, caproic acid is the highest in Luzhou-flavor, followed by lactic acid.

Acids in liquor can be divided into volatile acids and nonvolatile acids. Volatile acids include formic acid, acetic acid, propionic acid, butyric acid, caproic acid and octanoic acid. Formic acid is the most irritating, but its content is very small, while acetic acid is strong and high in content, which brings pleasant sourness and sourness to wine. But if the content is too high, the wine will have a sharp sour taste, while butyric acid has a pit mud taste and is slightly sweet. Some unsuccessful Luzhou-flavor wines contain more butyric acid and have outstanding odor. However, if the content is thin, it may be mixed with other aroma substances, or it may form aroma and aroma components. Hexanoic acid has pit mud taste and spicy taste, so Luzhou-flavor wine must have a certain amount of caproic acid, and if it is excessive, it will have a fat taste. Propionic acid smells bitter and sweet, soft in the mouth, and astringent in excess. Octanoic acid and fatty acids with long carbon chains are oily, but the content is not high.

Nonvolatile acids include lactic acid, malic acid, gluconic acid, tartaric acid, citric acid and succinic acid. Lactic acid is soft and brings good flavor to liquor. Lactic acid has a light aroma, which makes liquor mellow and rich, while excessive lactic acid has an astringent taste. Succinic acid harmonizes the taste of wine and is good for health. Limonin and tartaric acid have a long sour taste, which makes the wine refreshing and excessively biting. In short, these nonvolatile organic acids play a role in flavoring and alleviating violence in wine. As long as the content ratio is appropriate, it will make people feel refreshing, smooth and soft after drinking. Too high a content is sour and pungent.

Volatile fatty acids starting from propionic acid have a special smell. When butyric acid is too thick, it will sweat, while valeric acid, caproic acid and heptanoic acid have strong sweat smell, but this smell will gradually weaken with the increase of carbon atoms, and the smell of bitterness is less, but weaker. Acids with more than 8 carbon atoms have a faint acidic gas and a slight fatty smell.

Volatile acetic acid and nonvolatile lactic acid are the two most abundant acids in liquor. They are not only important flavor substances in liquor, but also precursors of many flavor substances. The content of acetic acid in general liquor is close to lactic acid, while the content of lactic acid in high-quality liquor is greatly increased.

In a word, organic acids have both fragrance and taste. Organic acids with less carbon atoms can help fragrance, which is an important fragrance-assisting substance. Acids with more carbon atoms, or nonvolatile acids, are important flavor substances, which play a role in seasoning and alleviating violence in wine. But pay attention to their contents and the proportional relationship between them.

(3) Alcohol: Alcohol plays an important role in liquor. They are the main substances of alcohol sweetness and aroma AIDS in liquor, and also the precursors of aroma substances. Alcohol reacts with acid to produce various esters, thus forming the special aroma of liquor.

Besides ethanol, liquor contains the following main alcohols: methanol, propanol, tert-butanol, sec-butanol, isobutanol, tert-amyl alcohol, sec-amyl alcohol, isoamyl alcohol, n-amyl alcohol, hexanol, heptanol, octanol, n-butanol, glycerol, isopropanol, 2.3- butanediol and so on. Liquor contains a small amount of higher alcohols, which gives liquor a special aroma, sets off the ester aroma and makes the aroma more complete. These higher alcohols are not only aromatic components in liquor, but also flavor substances, and most of them smell like alcohol, which lasts for a long time and has stamina, and has a certain effect on liquor flavor. The content of these higher alcohols in liquor and the proportion of various alcohols have an important influence on the flavor of liquor.

These higher alcohols taste bad. Except for isoamyl alcohol, which is slightly sweet (slightly astringent), other alcohols are bitter, and some are bitter and long. Therefore, their content must be controlled within a certain range. Too little content will lose the traditional liquor style; Drinking too much will lead to bitterness, have a bad influence on wine and get drunk easily. Wine with high alcohol content often brings unbearable bitter and strange taste, which is called "fusel oil taste".

On the one hand, these higher alcohols are harmful components in liquor, and only excessive amounts are harmful to the flavor of liquor. On the other hand, an appropriate amount of higher alcohols is an indispensable aroma and taste component in liquor. If the base liquor of liquor is treated very cleanly and no higher alcohols are added, that is to say, there is no or a great lack of these higher alcohols in liquor, the taste of liquor will be very weak. If 0.03% higher alcohol is added to diluted alcohol, liquor will produce a certain flavor, so it is also a substance that plays an important role in the composition and style of liquor. The key is that their content must be appropriate, not too much. At the same time, the proportion of fusel oil to acid and ester, and the proportion of various types in fusel oil also have an important influence on the flavor of liquor. If the alcohol-ester ratio is high, fusel oil will feel unpleasant, while if the alcohol-ester ratio is moderate, even if the fusel oil content is slightly higher, it will feel unpleasant. The ratio of alcohol to ester in liquor should be less than1; For example, the ratio of acid: ester: higher alcohol = 1: 2: 1.5 is more appropriate. If higher alcohols are higher than esters, the bitterness of fusel oil in liquid liquor will appear. On the contrary, if higher alcohols are lower than esters, the taste of wine tends to be mild and the bitterness decreases. In addition, if the ratio of isobutanol to isoamyl alcohol in wine is appropriate (1: 2 ~ 2.5), the odor caused by fusel oil can also be significantly reduced.

Besides the above-mentioned higher alcohols, there are also some polyols in liquor, such as glycerol, 2,3-butanediol, cyclohexanol and mannitol, which are sweet substances in liquor. Glycerol has a sweet taste, which makes wine feel natural. If you add the right amount, it will make the wine feel soft and strong. Pentaerythritol (erythritol) is twice as sweet as sucrose, pentanol (arabitol) is also a sweet substance, and hexanol (mannitol) has a strong sweetness, which makes wine have the sweetness of fruit. These polyols are viscous liquids, which can give liquor a full and mellow feeling.

β-phenylethanol in alcohol is an important component of liquor flavor, which gives liquor a rose-like fragrance with strong persistence, while excessive amount brings bitterness. Alcohols can also combine with fatty acids to form esters, which more or less increase the aroma of wine.

The content of higher alcohols in liquor should be below 0.3 g/ 100 ml, and the total amount of fusel oil in national standard physical and chemical indexes should not exceed 0. 15 g/ 100 ml. The higher alcohols mentioned above actually refer to alcohols with -OH groups with more than 2 carbon atoms in the carbon chain. Fusel oil sometimes refers to higher alcohols in general, and the analysis index actually refers to the amount of isobutanol and isoamyl alcohol. Polyol refers to alcohols containing more than two -OH groups in the molecule. It tastes sweet and slightly bitter, and it is very stable in wine, making wine sweet and soft.

Isoamyl alcohol, isobutanol, n-butanol and hexanol are commonly used in wine blending, and a small amount of glycerol and 2.3- butanediol are often added to improve the quality of wine and increase the naturalness. In addition to the above alcohols, there is also a kind of methanol with only one carbon atom in liquor. Methanol is very toxic, and 4 ~ 10g can cause serious poisoning. It is harmful to the blind spots of human nervous system and optic nerve, accumulates in the body and is not easy to be excreted. Its metabolites in human body are formic acid and formaldehyde, and the toxicity of formic acid is 6 times greater than that of methanol, and the toxicity of formaldehyde is 30 times greater than that of methanol. Therefore, according to national standards, the methanol content in whole grain liquor should be 0.04 g/ 100 ml, and the methanol content in liquor with dried melons and substitutes should be 0. 12/ 100 ml.

In liquor, besides the above alcohols, the main component is ethanol, which is slightly sweet. Alcohol determines alcohol content, and the higher the alcohol content, the stronger the alcohol content. The degree of liquor varies with drinking habits and manufacturing habits in different places. The alcohol content is above 60 degrees in the north and 46 ~ 55 degrees in the south. Some people mistakenly think that the higher the alcohol content, the better the quality. This is a wrong view. Judging from the quality of wine, at 53 ~ 54 degrees, the affinity between alcohol molecules and water molecules in wine is the strongest, the alcohol content of wine is good, the taste of wine is the most harmonious, and it is also the most refreshing to human taste. Maotai liquor did this skillfully. Hard liquor with high alcohol content is also very harmful to people, especially if it is drunk all the year round, it is easy to cause chronic alcoholism and will cause diseases to the nervous system, stomach, duodenum, liver and blood vessels. For people's health, reducing alcohol content is a problem worthy of attention. So one of the development directions of liquor is to reduce the alcohol content. Of course, this is still a complicated problem. To reduce alcohol content, not only should we overcome the turbidity caused by low alcohol content, but also a series of problems need to be studied and solved so as not to affect the inherent flavor of liquor. In addition, consumers also have a process of gradual adaptation. At present, the alcohol content of Fen-flavor liquor is generally 62-65 degrees, Luzhou-flavor liquor is 60 degrees, and Maotai-flavor liquor is 52-55 degrees.

(4) Flavor characteristics of carbonyl compounds Aldehydes with carbonyl groups play a certain role in the formation of the main aroma of wine, and the aroma of wine is closely related to the content and types of aldehyde compounds. Aldehyde has a strong smell. Aliphatic lower aldehydes have pungent odor, and the carbon chain length increases, reaching the highest value at C8 ~ C 12, and then decreases sharply with the increase of carbon chain. In liquor, even carbon atoms are more fragrant than aldehydes with adjacent odd carbon atoms.

Aldehydes in liquor include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, heptaldehyde, furfural and acetal.

A small amount of acetaldehyde is a beneficial aroma component in liquor. It is fruity, sweet and astringent. Generally, high-quality liquor contains more than 20 mg of acetaldehyde per 100 ml. Acetal was obtained by further condensation of acetaldehyde and ethanol. Acetal content in liquor is relatively large, and some high-quality liquors can reach more than 100 mg/ 100 ml, becoming one of the main components in liquor. The content of these two components in high-quality liquor is 2 ~ 3 times higher than that in ordinary liquor. They have obvious fragrance and head fragrance, and have a good flavor enhancement effect when appropriate. The content of other aldehydes is very small, and isovaleraldehyde has a better fragrance and is as sweet as almonds. Furfural is slightly golden yellow and has the bitter taste of banana. However, when the furfural content is too high, it is extremely bitter and disgusting, and furfural is harmful to human body. However, in the seasoning of liquid liquor, a very small amount of furfural is sometimes added, which plays a great role in solving the alcohol taste of liquid liquor, but the content should not exceed the Food Hygiene Standard promulgated by the state. Sometimes in liquor production (or alcohol production), acrolein is often produced when it is abnormal. This acrolein is not only dazzling, but also bitter for a long time. Acrolein and propylene alcohol are tearful substances, which are extremely harmful to human body. It is necessary to strictly put an end to the use of alcohol containing acrolein to make wine. When you need it, you must handle it several times. After laboratory analysis, it can only be used as a wine base if there is basically no acrolein.

The content of aldehydes in wine should be moderate, which is beneficial to the taste of wine, but excessive aldehydes will make white wine have a strong stimulating taste and spicy taste, which will lead to dizziness after drinking this wine. Aldehydes are the main source of spicy taste in wine. As long as there is a small amount of acetaldehyde, it will react with ethanol and volatile acids in the wine to form smelly substances, which will make the wine spicy. As a stimulating hobby, it is of course necessary for wine to be moderately spicy, but too spicy will hurt the flavor of wine and be harmful to the health of drinkers.