Ideas That Changed The Rum World
Category: Alcohol Proofing & Taxes
Alcohol producers have, by the very nature of their trade, been interested in quantifying
the alcohol they produce. Many such devices have been used historically, but the development of high-precision measuring devices did not take off until governments started applying additional alcohol taxes on these beverages.
It quickly became evident that producers and auditors had to standardize their procedures and equipment, in order for them to reach agreement as to the actual alcohol strength of a beverage.
Idea: Hydrometer
A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted
with mercury or lead shot to make it float upright. The liquid to test is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity.
Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity. The operation of the hydrometer is based on Archimedes’ principle, which states that a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid. Thus, the lower the density of the substance, the farther the hydrometer sinks.
An early description of a hydrometer appears in a letter from Synesius of Cyrene to the Greek scholar Hypatia of Alexandria. In Synesius’ fifteenth letter, he requests Hypatia to make a hydrometer for him. Hypatia is given credit for inventing the hydrometer (or hydroscope) sometime in the late 4th century or early 5th century.
According to the Encyclopedia of the History of Arabic Science, it was used by Abū Rayhān al-Bīrūnī in the 11th century and described by Al-Khazini in the 12th century.