Alcohol Diversity: Are All Drinks Chemically The Same?

Alcohol is an organic compound composed of hydrogen, oxygen, and carbon atoms. The three main types of alcohol have different combinations of these three elements, and their molecular structures vary. The term alcohol originally referred to the primary alcohol ethanol (ethyl alcohol) , which is used as a drug and is the main alcohol present in alcoholic drinks. However, there are many other types of alcohol, including methanol, which is toxic and used in manufacturing processes, and isopropyl alcohol, which is used in cleaning products and as a disinfectant. The flavour composition of alcoholic beverages is influenced by volatile and non-volatile compounds, which can include aliphatic carbonyl compounds, monocarboxylic acids, terpenic compounds, and more.

Different types of alcohol

Alcohol is a type of organic compound that carries at least one hydroxyl group bound to a saturated carbon atom. Alcohols can be differentiated based on the presence and location of this hydroxyl group, which can change the physical and chemical properties of the alcohol.

There are three main types of alcohol: primary, secondary, and tertiary. Primary alcohols have a hydroxyl group attached to only one single alkyl group, with common examples including methanol and ethanol. Secondary alcohols have a hydroxyl group attached to two alkyl groups, which may be structurally identical or different. Tertiary alcohols have a hydroxyl group attached to a carbon atom, which is connected to three alkyl groups.

When consumed by humans, ethanol is the only type of alcohol that is safe for drinking. It is the main alcohol present in alcoholic drinks and is produced by the fermentation of yeast, sugars, and starches. It is commonly found in drinks such as beer, wine, and spirits. Other types of alcohol, such as methanol and isopropanol, are poisonous to humans and used for cleaning and manufacturing instead.

Alcoholic beverages can be made by fermenting different types of grains, fruits, and vegetables, creating ethanol. Some alcohols then undergo an additional process called distilling, which removes water and increases the alcohol content. This process results in drinks with higher alcohol concentrations, such as spirits like vodka, rum, and tequila.

Liquor is typically divided into six main categories: gin, vodka, whiskey, tequila, rum, and brandy. However, there are many other types of alcoholic drinks, including beer, ale, cider, wine, and liqueurs, each with varying levels of alcohol content and unique production processes.

Alcohol toxicity

Alcohol is a type of organic compound that carries at least one hydroxyl group ( −OH) functional group bound to a saturated carbon atom. The term alcohol originally referred to the primary alcohol ethanol (ethyl alcohol), which is the main alcohol present in alcoholic drinks. Other types of alcohol include methanol, propanol, and butanol. Methanol is the most common industrial alcohol.

Ethanol toxicity, or alcohol intoxication, occurs when a large amount of alcohol is ingested, affecting multiple organ systems. The primary site of action in acute toxicity is the central nervous system, where it increases central nervous system (CNS) inhibition and decreases excitation. Gamma-aminobutyric acid (GABA), a neurotransmitter, binds to receptors allowing chloride to enter the cell, which decreases cellular excitability. Alcohol binds strongly to these GABA receptors, activating the inhibitory cascade, which results in sedation, cognitive dysfunction, and decreased coordination. With chronic alcohol use, the number of GABA receptors is increased, requiring more and more alcohol to create the same level of inhibition. This is known as tolerance.

The severity of symptoms of ethanol toxicity depends on the blood alcohol concentration (BAC). At a BAC of 0 to 0.05%, one would expect to see relaxation, increased talkativeness, and decreased fine motor control. At a BAC of 0.05% to 0.1%, impaired judgment and coordination develop. From 0.1% to 0.2%, one sees gait instability, slurred speech, and mood and behaviour changes. At a BAC of 0.2% to 0.4%, nausea and vomiting, hypothermia, dysarthria, amnesia, diplopia, and nystagmus occur. With a BAC of greater than 0.4%, respiratory depression can occur, followed by coma and even death.

An alcohol overdose, or alcohol poisoning, occurs when there is so much alcohol in the bloodstream that areas of the brain controlling basic life-support functions, such as breathing, heart rate, and temperature control, begin to shut down. Symptoms of alcohol overdose include mental confusion, difficulty remaining conscious, vomiting, seizures, trouble breathing, slow heart rate, clammy skin, dulled responses, and extremely low body temperature. Alcohol overdose can lead to permanent brain damage or death.

Age, sensitivity to alcohol (tolerance), sex, speed of drinking, medications, and amount of food eaten can all be factors that affect the impact of alcohol on an individual. Additionally, ingesting alcohol with other drugs can intensify their individual effects and increase the risk of an overdose.

Alcohol manufacturing

In scientific terms, alcohol is a range of molecules formed when oxygen and hydrogen atoms bind with a carbon atom. However, when it comes to alcoholic drinks, the alcohol is a specific small molecule called ethanol. Ethanol is typically made by fermenting the sugars in grains, fruits, or vegetables. For alcoholic drinks, different raw materials are used to create different types of drinks. For example, grain is used to make whisky or beer, grapes to produce wine, apples to produce cider, and potatoes to make vodka. In each case, yeast is added to ferment the sugars in the fruit, grain, or vegetable and turn them into alcohol.

The term alcohol originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. The suffix -ol appears in the International Union of Pure and Applied Chemistry (IUPAC) chemical name of all substances where the hydroxyl group is the functional group with the highest priority. Alcohols can be classified into three types: primary, secondary, and tertiary alcohol. Primary alcohols are those where the carbon atom of the hydroxyl group (OH) is attached to only one single alkyl group, such as methanol (propanol) and ethanol. Secondary alcohols are where the carbon atom is attached to two alkyl groups on either side, and these groups may be structurally identical or different. Tertiary alcohols feature a hydroxyl group attached to the carbon atom, which is connected to three alkyl groups.

Many alcohols are produced by hydroxylation, the installation of a hydroxy group using oxygen or a related oxidant. Hydroxylation is the means by which the body processes many poisons, converting lipophilic compounds into hydrophilic derivatives that can be more easily excreted. Many industrial alcohols, such as cyclohexanol, are produced by hydroxylation. In the Ziegler process, linear alcohols are produced from ethylene and triethylaluminium, followed by oxidation and hydrolysis. Many higher alcohols are produced by the hydroformylation of alkenes followed by hydrogenation.

The flavour composition of alcoholic beverages comes from raw materials, fermentation, and the wooden casks in which they are matured. During maturation, unpleasant flavours, probably caused by volatile sulphur compounds, disappear. Extensive investigations on the maturation of distillates in oak casks have shown that many compounds are liberated by alcohol from the walls of the casks. Lignin plays an important role and is responsible for the occurrence of some aromatic aldehydes and phenolic compounds. Many terpenic compounds, ketones, alcohols, aldehydes, esters, lactones, phenols and phenol ethers, and acids have been identified as the flavour components of H. odorata, which is used to flavour Russian vodka.

Alcohol use disorder (AUD)

The risk factors for developing AUD are varied and include genetic predispositions, with hereditability accounting for approximately 60%, as well as environmental influences. Parental drinking patterns may also play a role in a child's likelihood of developing AUD later in life. Mental health conditions, such as depression, post-traumatic stress disorder, and attention deficit hyperactivity disorder, are associated with an increased risk of AUD, and individuals with a history of childhood trauma are also particularly vulnerable.

AUD can manifest in several ways and can be classified as mild, moderate, or severe depending on the number of symptoms present. Some signs that may indicate AUD include an inability to relax or fall asleep without drinking, drinking alone or in secret, drinking in the morning, using alcohol as an escape from feelings, drinking and driving, mixing alcohol with medications, drinking during pregnancy or when caring for children, and continued alcohol use despite negative consequences.

The treatment for AUD typically involves a combination of behavioural therapies, mutual-support groups, and medications. Behavioural treatments, also known as alcohol counselling or talk therapy, aim to change drinking behaviour and build motivation and skills to cope with cravings and prevent relapse. Mutual-support groups provide peer support and can be especially helpful in preventing a return to drinking. Three medications currently approved by the U.S. Food and Drug Administration to help reduce alcohol consumption and prevent relapse are naltrexone, acamprosate, and disulfiram.

While AUD is a chronic condition with a risk of relapse, it is treatable, and individuals can achieve and maintain recovery with appropriate interventions. However, it is important to recognise that AUD treatment may need to be tailored to the individual, as one approach may not work for everyone. For those with severe AUD or end-stage AUD, medical supervision and specialised treatment facilities may be necessary to manage withdrawal symptoms and ensure a safe recovery process.

Alcohol flavour compounds

Alcoholic beverages contain both volatile and non-volatile flavour compounds. The flavour compounds in alcoholic drinks originate from three sources: raw materials, fermentation, and the wooden casks in which they are matured.

Volatile compounds include aliphatic carbonyl compounds, alcohols, monocarboxylic acids and their esters, nitrogen- and sulphur-containing compounds, hydrocarbons, terpenic compounds, and heterocyclic and aromatic compounds. Terpenic compounds, ketones, alcohols, aldehydes, esters, lactones, phenols and phenol ethers, and acids have been identified as the flavour components of the grass Hierochloe odorata, which is used to flavour Russian vodka. Tyrosol and tryptophol, which are formed during fermentation, have been found in many beers, as has acetic acid. Phenethyl alcohol, an aromatic fusel alcohol with a rose-like odour, is another example of a flavour compound found in beer.

Non-volatile extracts of alcoholic beverages include unfermented sugars, di- and tribasic carboxylic acids, colouring substances, tannic and polyphenolic substances, and inorganic salts.

Flavoured alcoholic drinks may contain added synthetic substances and ingredients isolated from herbs and spices. For example, vermouths, aperitifs, bitters, liqueurs, and some flavoured vodkas contain different essential oils or their mixtures, synthetic products, and colouring substances. Citrus oils, which are composed of many compounds, including terpenes, sesquiterpenes, aldehydes, alcohols, esters, and sterols, are widely used for beverage flavouring. Other popular flavours for alcoholic drinks include peach, nectarine, mint, basil, cranberry, and raspberry.

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