Apart from ethanol that has toxic effects, there are to be found in alcohol drinks a range of substances, known as congeners that give alcoholic drinks their flavor and texture and taste. Vodka contains very few congeners and has little taste or flavor. Spirits such as bourbon and dark rum have many congeners that contribute toxic effects to a hangover.
White wine does not have as many congeners as red wine. Lagers contain fewer congeners than dark brown ales and barley wines. In general home brews of beer or wine contain fewer congeners. There is also less, if any, preservative in brews home-made with fresh yeast and fresh ingredients.
Congeners are natural by products of the distillation and fermentation process. The word congeners means things that are “born together”. By products of fermentation include acetaldehydes, and esters, including ethyl esters, and fusel oil. Fusel comes from the German language and literally means “bad spirits”.
There are four main alcohol types in fusel oil. The result of fermenting yeast is always to produce these other alcohols in addition to ethanol, that add flavor to alcohol drinks.
Fusel oil is often blamed as creating the hangover effects when drinking too much alcohol. Scientifically, it is a bit of a mystery as to why yeasts make fusel oil, as it is not part of the basic fermentation process whereby yeasts gain energy, nor does it seem to provide the yeast with any major benefit. When yeasts are modified so that they cannot produce the fusel oil alcohols, yeasts will still manage to make some form of fusel oil as if under some type of compulsion. Even mutated forms of yeast will make some form of fusel oil as part of the fermentation process, fusel oil is a component of all our alcohol drinks.
Fusel oil it would seem cannot effectively be modified out of alcohol production, so it will remain as one of the toxins to be aware of in our alcohol drinks. The less flavored the alcoholic drink is, generally there will be less fusel oils that contribute to alcoholic hangovers. Also better quality alcohol products usually contain fewer congeners. Better to have one or two expensive drinks than drink more of cheaper products when you are trying to limit your intake of alcohol and related congeners
As wine is matured, the potency of the congeners reduces so drinking wine that is more fully matured helps to reduce our exposure to congeners and hangovers.
Interesting studies have been done on congeners and aggression, which show a different mechanism for ethanol and congener effects.
Ethanol appears to have a depressive effect at low and high doses, with an intermediate amount having a facilitating effect. A study of Siamese fighting fish showed that aggression increased in an ethanol solution, decreased in a solution of bourbon and congeners, and aggression was greatly reduced in the solution that contained only the congeners.
Aggression and alcohol drinking is of concern today because of the widespread aggression that occurs with alcohol drinking in public places. Chronic alcohol drinking can also result in domestic violence between husbands and wives, between de facto partners and young children.
Many years ago there was a scandal when it was found that a famous producer of wines had been adding antifreeze to its wine. Modern antifreeze is usually ethylene glycol, a clear, sweet tasting, odorless liquid. It has been mistaken for spirits and drunk, and some alcoholics will drink antifreeze if there is no alcohol around. Antifreeze is not toxic in itself, but becomes highly toxic in the process of being broken down by alcohol dehydrogenase in the liver, into toxic chemicals including oxalic acid. An alcohol dehydrogenase inhibitor – Antizol, is a drug that has been approved for antifreeze poisoning.
There is a natural alternative. One of the traditional remedies for hangovers is rhubarb, also known as Da Huang, the Chinese equivalent. Rhubarb root acts to reduce alcohol hangover effects by inhibiting the production of alcohol dehydrogenase. In some ancient brewing recipes extracts from rhubarb root were always included.
Additives to alcohol drinks have also included bright coloring and sweet flavors. The marketing of “alco-pop” drinks, such as highly colored, flavored vodka, has drawn criticism as making alcohol drinks attractive to young people. Alcohol producers that include stimulants such as caffeine and taurine are currently the subject of much debate in Canada. Although some manufacturers no longer produce high alcohol energy drinks, there are great risks associated with drinking pre-mixed alcohol energy drinks in Canada.
The toxic forms of alcohol and additives, contained in alcohol drinks, are best avoided completely by young people. Adults too, should consider alternatives to drinking alcohol for both recreation and stress relief. Freeing the body of chemical toxicity, rather than increasing the load, is a far better approach to the problem of stress reduction in the modern world.