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Why does a 30ml/1 fl oz serving of 40% ABV spirit have 65cals, not 85?

If alcohol is 7kcal/g, and a spirit eg. whisky or vodka is 40%, does that not mean 0.4*7=2.8kcal/ml of spirit, meaning that a 30ml serving would be 30*2.8=84kcal/30ml - I'll round that to 85. But on every bottle/company's website (or wherever else I've found official information), it always says ~65kcal/30ml. Would that not mean 65÷30=2.17kcal/gram - round to 2.2, and 2.2÷7=0.32g alcohol/ml, therefore 32%ABV. What am I missing? Does ethanol have a significantly different density to water?

Answer

Yes. Ethenol is .79 g/cc while water is 1 g/cc. https://van.physics.illinois.edu/qa/listing.php?id=1738#:~:text=Learn%20more%20physics!&text=Well%2C%20I%20cannot%20speak%20for,1.0%20g%2Fcc%20for%20water.