The secret to strength of absinthe? Eh,... alcohol

A detail from The Absinthe Drinker, painted by Edgar Degas in 1876 at the height of the drink’s popularity.

AN analysis of century-old bottles of absinthe — the kind once quaffed by the likes of van Gogh and Picasso to enhance their creativity — may end the controversy over what ingredient caused the green liqueur’s supposed mind-altering effects.

The culprit seems plain and simple: the century-old absinthe contained about 70% alcohol, giving it a 140-proof kick. In comparison, most gins, vodkas and whiskeys are just 80- to 100-proof.