Alcohol

Alcohol in terms of its molecular structure is C2H5OH. Thus to a spine of two carbon atoms are attached five hydrogen atoms and a hydroxyl (oxygen-hydrogen) group. That constitutes a fairly simple structure carrying rather little information, and alcohol has therefore sometimes been referred to disparagingly by biochemists as a 'stupid' molecule. Its structure is much smaller and less interesting than those of such complex mind-acting chemicals as heroin, nicotine or the cannabinol which is the core drug constituent of cannabis.

Alcohol at room temperature is a colorless liquid which in pure form is astringent and unpleasant on the tongue. Dilution makes it less unpalatable, and alcohol and water mix together easily. Spirits are about 40 per cent absolute (pure) alcohol; port, sherry and other fortified wines 15-20 per cent; and wine around 12 per cent. A standard beer will be about 4 per cent alcohol by volume, although strong beers can be anything up to I 0 per cent. What gives these various beverages their attractive and distinct tastes is not however their alcohol (diluted or otherwise), but the chemicals which have got into them in the course of production. It is possible to produce a beer from which nearly all the alcohol has been extracted and which still tastes reasonably like beer. But take out even a little of the complex flavoring given by sugar, hops, barley and so on, and the residual drink will be a pale imitation or even a parody of the original. Put unkindly, it is the dirt in the drink which makes it attractive to the nose and the palate, and which turns a mixture of alcohol and water into a good beer, a fine wine or a famous malt whisky. Vodka is relatively free from contaminants, and hence relatively odorless and tasteless.

The alcohol that is used in beverages is called ethanol. It is actually only one of many different types. The alcohol a nurse rubs on the skin as a disinfectant before giving an injection or drawing a blood sample is not the same-it is isopropyl alcohol. The chemical structures of most alcohols make them quite toxic to the human body. Ethanol is the only one that should ever be consumed, but people regularly poison themselves with other alcohols. For example, methanol, produced in home-distilling operations, can cause blindness. A case of methanol poisoning requires immediate medical attention. Therefore, home-distilled liquor, or "moonshine," should always be avoided.

Fermentation

The ultimate source of all beverage alcohol is the breakdown of naturally occurring carbohydrate (starch or glucose) to ethyl alcohol, water and carbon dioxide, by the action of enzymes. Most commercial beer derives from the action of brewers' yeast on barley or other cereals, with hops added to some beers for flavoring. Commercially available wine derives from the breakdown of the sugar contained in the juice of the grape by the yeasts which are present in the bloom on the fruit's surface, although laboratory-bred yeast may also be used. Cider is made from apples, and perry from pears.

But if those are the materials which form the basis for the fermented alcoholic beverages which most societies drink, there are myriad other plant products which have at some time been employed in the production of alcohol, especially in developing countries. In North America, birch beer has been made from the sap of the same tree that provides covering for canoes, and a birch-based drink has also been drunk in Siberia. Chicha is a fermented drink made from maize, and has been consumed over wide areas of Central and South America from the pre-Columbian era onwards. In many parts of Africa, home production of beer has for centuries been a feature of rural culture, with maize, millet or sorghum the usual basis. Barley-based beers are brewed in the more northern parts of Africa, palm wine is a favorite drink in West Africa, and bananas and many other types of fruit are used for alcohol production within other local traditions. Rice wine is popular in the Far East. Other than in the Arctic regions, there is probably no part of the world where the abundance of nature aided by a kindly enzyme has not resulted in the availability of some sort of alcoholic drink. The flavor of these drinks may not always approach that of a real ale or a chateau-bottled claret -indigenous African beer may to the Western palate taste like a diluted porridge and even have a few dead flies floating in the billycan -but alcohol is alcohol and the common factor the world over.

So simple is the process of producing an alcoholic beverage by fermentation that early humans would have got hold of this technique as soon as it was possible to gather fruit, add water, and wait a few days for enzymatic action to do its work. These conditions probably imply the beginnings of a settled and agricultural way of life rather than a nomadic existence. Having emphasized the extreme simplicity of the basic process, it should be acknowledged that modern production of beer involves advanced technology, and brewing has developed a strong scientific base. Wine production also has its science, but in some ways stays closer to its ancient pre-industrial origins.

However primitive or advanced the technology, there is a limit on the alcohol concentration which can be achieved by any form of fermentation. This is set by the fact that when the concentration rises to a certain level, the yeast will be inhibited or killed by the alcohol which it has itself produced, and at that point the fermentation process will be shut down. Sake, the national drink of Japan, is produced by the action on rice of a non-yeast micro-organism (Aspergillus), and a concentration of about 17 per cent can be achieved before the fermentation is switched off. And that for practical purposes is probably the top alcohol concentration achievable for any beverage by natural fermentation.

Distilling as amazing innovation

For millennia the simple fact of alcohol-induced self-limitation on fermentation meant that there were ceilings on the strength of the product. To get drunk on a 12 per cent wine or a 4 per cent beer is none too difficult, although some of the traditional alcoholic drinks of the developing world have an alcohol content so low that it would require agricultural and brewing resources beyond that of any village to make widespread intoxication at all likely.

In the sixteenth century the age-old natural barrier to production of higher-concentration beverages was overcome by dissemination across Europe of the technology of distillation. Today we may view the bottles of spirits stacked on the slightly more secure shelves at the off-licence as a familiar part of the great drinks spectrum. But in the sixteenth century distillation must have looked like a revolutionary and threatening technology. Suddenly alcohol was available at more than three times the concentration at which people had previously seen or tasted it. All sorts of old balances between populations and their drinking were destabilized. The very word 'spirits' carried a dangerously magical message.

The origins of distillation go back at least 2,000 years. The process was known to the Greeks as early as the first century AD. In the third century AD, Alexander of Aphrodisias gave a description of how sea water could be distilled to produce drinking water. And in passing he mentioned the possibility of carrying out distillation on wine. As so often happened in the history of science and medicine, this Greek learning was transmitted to the Arab world, and then much later brought back to Spain and thence to the rest of Europe.

By the middle of the sixteenth century the use of distillation to provide concentrated alcoholic drinks had become a widely applied technology across the Continent. At first the resulting preparation was viewed primarily as a medicine, but before long it was the basis for a range of new beverages. The distillation of wine would give brandy to Europe and various similar spirituous drinks. From fermented grain with a little flavoring of juniper came gin -originally from Holland, with London gin a later unsweetened and competitive variety. Whisky is derived from various different cereals according to its country of origin -Scotch whisky, for instance, comes from malt and grain with caramel for coloring, the smoke of peat-fired kilns for flavor, and an esteemed spring water as carrier. Rum emerged as a distilled beverage based on molasses. Kentucky bourbon is a latecomer, dating from towards the end of the eighteenth century, made largely from a fermented maize mash which after distillation is aged in charred oak barrels.

Blood alcohol concentration

When swallowed, the alcohol is absorbed from the stomach and the small intestine. Absorption will be slowed by the presence of food, or can be somewhat speeded if the drink has been chilled or has been aerated with bubbles of carbon dioxide. Less concentrated drinks may have their alcohol more rapidly absorbed than stronger ones, so iced champagne drunk on an empty stomach can be an effective way of getting alcohol to the brain quickly. After a preliminary pass through the liver, some of the alcohol will be reaching the brain within minutes. The blood or brain alcohol level will then slowly increase for the next thirty to sixty minutes as the absorption of a single drink is completed. Several drinks taken together or spaced out in a series of drinks will result in the alcohol level going upwards longer and higher. But enormous variation in absorption rates can occur between individuals and on different occasions.

The blood alcohol concentration (BAC) which is achieved after any drink or drinking session will reflect a balance between, on the one hand, how much alcohol is absorbed and over what time, and, on the other hand, how quickly the body is getting rid of alcohol. The larger part of elimination (80 per cent) is achieved by metabolic breakdown in the liver, and a heavy drinker may be able to break down alcohol twice as fast as someone who drinks more lightly or occasionally. Some alcohol is excreted unchanged in the urine, and a little bit is breathed out through the lungs or lost in sweat. But the self-deceiving belief of old-time colonial hands that alcohol is relatively harmless in a hot climate, because it can be prodigiously sweated out, has no scientific basis.

When alcohol meets the brain

What happens when the absorbed alcohol gets to the brain? There can be no doubt that, so far as most people are concerned, when alcohol meets the brain the event is received as good news. Something subtly pleasant begins to happen. The average drinker is not likely to sit around and attempt to put into words what he or she is beginning to experience, but after a glass or two something wanted and familiar is usually being sensed. What is experienced psychologically will be modified by personality, previous experience with alcohol, expectations of what alcohol can do for the person concerned, the company and setting, and cultural beliefs. But behind all those important influences is the core fact that when alcohol reaches the brain a mind-acting drug will begin to impact on the brain cells and brain systems in a way which can produce or facilitate pleasurable alterations in mood.

Though a change of mood is the the first, obvious, wanted effect produced by alcohol, at the same time there will be produced physiological effects such as increased pulse rate, a rise in blood pressure, and an increased secretion of urine -consequences which are usually of no great immediate importance to the drinker.

There is a dose relationship for many of these effects, so that with more drink the pleasure is increased. Eventually, however, unpleasant effects come into play and drinking becomes aversive. The level of intake at which the response switches from pleasure to aversion varies greatly from person to person, but the wanted euphoria may be replaced by depression and maudlin misery. Nausea and vomiting may be other unwanted physical effects. In addition, there will very soon at ordinary levels of drinking be, with some variation between individuals, a dose-related impairment of reaction time, coordination and balance.

How alcohol acts on the brain and interacts with psychological expectations to produce its impact is a question which has during recent years attracted a great deal of research. A summary conclusion is that alcohol affects brain functioning by its capacity to interfere with the biological system of chemical messengers which is all the time regulating the balance between activity and inactivity in brain cells and brain circuitry. Alcohol does not directly key into receptor sites in the brain as do many other mind-acting drugs, but it produces its effects by cat's-pawing legitimate messengers. Through these mechanisms it will activate structures within the brain whose nerve-cell firing produces pleasure, while through other mechanisms it will dampen firing and produce sedation and impairment of coordination.

Alcohol as poison

Alcohol is potentially a poison in several different ways. The most banal poisonous consequence of drinking alcohol is that it can produce hangover -a state ranging from mild fragility to a thumping headache, nausea, the room spinning round, ghastliness, a short-lived resolve never to touch the stuff again. This state is in part the result of poisoning by the non-alcohol adulterants in the drink, but dehydration due to the diuretic effect of alcohol also plays a part. It is unpleasant, but no tangible harm is done other than perhaps a morning's work being lost.

Second, let's put in the list of potentially poisonous effects the fact that it is possible to die of an overdose of this drug. That, mercifully, is not too common an occurrence. Nevertheless, the drunk in the police cell has all too often been found dead in the morning as a result of respiratory depression caused by alcohol, complicated perhaps by inhaled vomit, and sometimes also by the capacity of alcohol to lower the blood-sugar level. Death by alcohol overdose occurs rather easily when this drug is mixed with sedatives, tranquillizers or opioids such as methadone or heroin, and many a sad fatality has happened that way.

Third, alcohol is a poison because, either directly or because of the associated malnutrition which tends to go with heavy alcohol use, it can physically damage body tissues and impair body systems. There is hardly any type of tissue which is not vulnerable if excessive drinking is long continued -brain, nerves, muscle, liver, heart.

Fourth, chronic exposure to alcohol carries a risk for certain types of cancer.

Fifth and lastly, through its capacity to impair coordination and judgement, alcohol can cause many types of accidents. It may also at times lead to violent behavior or contribute to the risk of suicide.

So much for a brief factual description of alcohol the molecule. But the objective facts are only a small part of the total meaning which we give to drink.