Alcohol as fuel and drug

2010-04-29

in Geek stuff, Science

I occasionally encounter people who are surprised to learn that alcohol itself contains many of the calories contained in alcoholic drinks. In some sense, the surprise is understandable; after all, we think of alcohol as a drug and a poison more than as a food. That being said, when ethanol enters the human body, it “is converted into acetaldehyde by alcohol dehydrogenase and then into acetic acid by acetaldehyde dehydrogenase.” Both of these reactions produce energy that your body can use.

In another sense, it is a bit obvious that ethanol is full of energy. Remember, alcohol has been used before as a fuel for vehicles, and even for rockets. Gasoline contains about 32 megajoules of energy per litre. By comparison, pure ethanol contains 23.5 megajoules: 73% of what is in the gasoline.

As a consequence, vodka (40% ethanol) contains 9.4 megajoules per litre: about 30% of what is in gasoline. So, to get a sense of the energy content of your drink, multiply the quantity of pure ethanol it contains by 0.73. Then, think about the energy that volume of gasoline would release, when burned. A six pack of beer (two litres at 5% alcohol) contains about as much energy as as two shotglasses (70mL) full of gasoline. A bottle of wine (750mL at 12% alcohol), is about the same.

Expressed another way, a bottle of wine contains enough energy (2.1 megajoules) to lift a small apple 2.1 million metres. It also represents the same amount of energy as a 2.1 tonne vehicle going 160km/h. A drop of beer contains 100 joules.

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{ 4 comments… read them below or add one }

Milan April 29, 2010 at 8:05 pm

Not everyone misses the fuel/drug connection. In Season 9, Episode 4 of ‘The Simpsons,’ Homer imagines himself alternating between drinking from the pump and filling his car at a fuel station for alcohol powered vehicles, saying: “One for you, one for me. One for you, one for me.”

XUP April 30, 2010 at 9:10 am

My post today is about alcohol, too!!

I would really enjoy a glass of wine with my supper every night, but I don’t for this very reason. There is a very noticeable effect on my waistline whenever I drink too often (Christmas or other holidays for instance). I don’t understand how the Europeans can do it and still stay so slim.

. October 16, 2016 at 9:06 pm

Most countries get more calories from alcohol than soft drinks – study

Data suggests tackling Britain’s drink problem could be more important for health than targeting sugar consumption

. October 16, 2016 at 9:07 pm

“Of 24 countries tracked by the data analysts Euromonitor International, all but one have higher daily calorie consumption from alcoholic drinks than sugary beverages. In the UK, adults are consuming more than 106 calories per head every day from alcoholic drinks, compared with 98 from sugar-sweetened drinks.

The highest calorie intake from alcohol is in South Korea, with nearly 168 calories a person each day and only 44 calories from sugary drinks. Also high are Poland, the Czech Republic, Finland and Germany while – of the countries examined – only the people of Taiwan get more calories from sweet drinks than alcohol. The US was not included.”

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