Whether it is champagne fizzing on the tongue, a hoppy beer coating the palate,
or a plummy wine staining the lips, alcohol announces itself instantly.
First there is a faint burning sensation, a little chemical spark, as the thin mouth membranes absorb a drop.
If the stomach is empty, the booze starts to pass into the bloodstream within minutes—
and then reaches almost every cell and tissue in the body.
The secret to its rapid transit is in its chemistry.
Ethanol, to give booze its proper name, is a tiny, agile molecule.
It has a backbone of two carbon atoms and is soluble in water.
It can hop over the blood-brain barrier like a ninja.
And then the fun begins.
By gatecrashing our brains, alcohol has shaped human history,
from our ancestors' descent from the trees to the formation of modern cities.
Yet because it brings misery and sickness as well as joy and conviviality,
our species' love affair with it is on the rocks.
Sales are sliding in rich countries; some think global consumption has peaked.
Is the greatest party of all time coming to an end?
To answer this question one needs to understand a relationship whose molecular fingerprints are first visible millions of years ago.
A good place to start is with biochemistry.
Ethanol is so toxic that most animals that consume it either quickly get drunk or poison themselves.
Humans, unusually, have a pair of enzymes that turf it out like night-club bouncers.