What is alcohol? Ingredients, chemicals and manufacture
What is alcohol, how is it made and how does it affect the body?
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In purely scientific terms, alcohol is the name for a whole range of molecules that are formed when oxygen and hydrogen atoms bind with an atom of carbon.
But when it comes to alcoholic drinks, all of the alcohol is a specific small molecule called ethanol – and if affects your body every time you drink.
When you drink alcohol, ethanol molecules are absorbed into your blood and, being small, they travel to virtually all parts of your body, including your brain.
Alcohol causes chemical changes in your brain, supressing normal activity in the area that controls inhibition.1 So it has a depressant effect on the brain, which then has to readjust as the alcohol wears off (when it's been metabolised – broken down by your body’s systems. That’s why alcohol can contribute to feelings of anxiety.
Alcohol is toxic2 – so your body has to work to get rid of it from your system every time you drink. Consuming several alcohol drinks in a short space of time puts you at risk of acute alcohol poisoning, and drinking heavily for months or years increases your risk of developing seven different types of cancer and other serious health problems.
The UK Chief Medical Officers low risk drinking guidelines advise that, if you decide to drink, it’s safest for both men and women to drink no more than 14 units of alcohol a week, spread over three or more days with several drink-free days, and no bingeing.
Because alcohol can affect the way you think and feel, it’s recognised as a ‘psychoactive substance’ by the World Health Organization, putting it in the same broad category as other drugs, including many illegal ones.3
However, alcohol isn’t legally classed as a drug in the UK. But the effects it can have on the safety and health of the person drinking it, as well as the impact it can have on wider society, mean there are laws in place to strictly control its sale – for example making it illegal for under-18s to buy alcohol.
Alcohol is made by putting grains, fruits or vegetables through a process called fermentation. This is a chemical reaction where yeast or bacteria react with the sugars in the other ingredients to produce ethanol (the alcohol in the drink) and carbon dioxide (which can mean the drink has bubbles).
One unit of alcohol is 10ml (millilitres) or 8g (grams) of pure alcohol. It takes an average adult around an hour to process one unit so that there's none left in their bloodstream – and the more you drink, the longer it takes.
Find out more about alcohol units
Wine and cider are made by fermenting fruit, while fermented cereals such as barley and rye form the basis of beer and spirits. Spirits also go through a process called distillation – where a proportion of the water is removed, leaving a stronger concentration of alcohol in the final product.
The alcohol content of a drink is affected by how long it's left to ferment. And there is now a wider range than ever of alcohol-free and low alcohol versions of beer, wine and spirits which are often made the same way as traditional alcoholic drinks, but have an additional stage of production to remove the alcohol while preserving as much as possible of the elements that give the drink its taste and appearance.
Reducing the amount you drink, or stopping drinking completely, can help you keep your risks from alcohol low. Try these tips to get started:
If you choose to drink alcohol, the UK Chief Medical Officers’ (CMOs) low risk drinking guidelines advise it’s safest for men and women to drink no more than 14 units a week, spread evenly over three or more days with several drink-free days.
Binge drinking harms your physical and mental health. One way to have a bit less is to alternate alcoholic drinks with a soft drink or water, and limit the total number of alcoholic drinks you have.
Knowledge is power, so staying on top of how much you drink is a great first step towards taking control and improving your health. Whether you want to cut down or go alcohol free, the MyDrinkaware app tracks units, calories and sleep side-by-side to help you achieve your goals.
There are lots of ways to enjoy more drink-free days - from easy activities to get in shape to tips to help you stay on track when temptation strikes. And we’ve got the advice that can help you get started.
Arming yourself with strategies and tips can help you or a loved one take small steps towards big results.
 Gan, G., Guevara, A., Marxen, M., Neumann, M., Jünger, E., Kobiella, A., Mennigen, E., Pilhatsch, M., Schwarz, D., Zimmermann, U.S. and Smolka, M.N. (2014). Alcohol-induced impairment of inhibitory control is linked to attenuated brain responses in right fronto-temporal cortex. Biological Psychiatry, 76(9), 698-707.
Last Reviewed: 16th February 2023
Next Review due: 16th February 2026