Whiskey Thread
There are rum nerds (me) that test spirits with hydrometers or mass spectrometers.
Johnny Drejer was the first to figure this out with inexpensive material.
http://www.drecon.dk/
https://thefatrumpirate.com/hydrometer-tests-2
The govts of Finland and Sweden do these test as well.
https://www.alko.fi/en/products/956621/Diplom-tico-Reserva-Exclusiva/
The European Union added regulations a few years back capping sugar additions at 20g per litre or you cannot call it rum, so some of these numbers will have changed...in the EU at least. Glucose, glycerol, and vanillin are used by some producers as well. FWIW, Jamaica has rules preventing any additions, and most rums from Barbados (except for Malibu and Plantation) don't have additives. Most French styles don't have additives. Spanish-style rums are usually the biggest offenders.
Drink what you like, but know what you drink is the motto.