underproof

If it didn't ignite, the solution had too much water in it and the proof was considered low or "underproof".

Army Rumour Service 2010

If it didn't ignite, the solution had too much water in it and the proof was considered low or "underproof".

Army Rumour Service 2010

- Jesus,  it's not underproof, he says, screwing the water out of his eyes.

cyclops 2010

But in some ways he was a kind of Thackeray several degrees underproof -- a small-beer

A History of the French Novel, Vol. 2 To the Close of the 19th Century George Saintsbury 1889

Multiply the result by the quantity of spirit, and divide the product by the number obtained by _adding_ the _required_ per centage overproof, or _subtracting_ the _required_ per centage underproof, to or from 100, as the case may be.

The Art of Perfumery And Methods of Obtaining the Odors of Plants George William Septimus Piesse 1851

Thus, spirit of wine at 56 per cent. overproof, signifies that 100 gallons of it are equal to 156 gallons of proof spirit; while a spirit at 20 per cent. underproof, signifies that 100 gallons are equal to 80 gallons at proof.

The Art of Perfumery And Methods of Obtaining the Odors of Plants George William Septimus Piesse 1851

Summer Edition is a bit underproof compared to regular Beefeater (80 proof, or 40% ABV, instead of 94 proof), but the delicate summer botanicals add a sweetness you might not often find.

Liquor Snob 2010

_overproof_ per centage _to_ 100, or _subtract_ the _underproof_ per centage _from_ 100.

The Art of Perfumery And Methods of Obtaining the Odors of Plants George William Septimus Piesse 1851