There are two types of hydrometers, the Specific Gravity Scale and the Oechsle Scale (named for Ferdinand Oechsle). Each has a different measurement scale.Generally, people familiar with the measurement systems in the United States and the United Kingdom refer to the Specific Gravity Scale. Others may prefer the Oechsle Scale.
We have created two entire sets of instructions for these hydrometers.
Click HERE to go the the Specific Gravity Instructions.
Click HERE to go the the Hydrometer with Oechslescale Instructions.


The hydrometer is a floating weight used to determine how many grammes one litre of must (unfermented grape juice) or wine weighs. There are two different sets of scales:

  1. Specific Gravity(S G) – most used by US/UK
  2. Oechsle Scale – named after Ferdinand Oechsle of Pforzheim, Germany

The hydrometer is winemaking’s most important instrument. To illustrate, in Germany, the entire legislation regarding winemaking is based on the hydrometer! And German winemaking legislation is the most stringent in the world.

Winemaking without a hydrometer is like driving a car without a steering wheel – there’s a strong chance of not getting to the destination. It is the only instrument necessary for the winemaker. Professional winemaking would be impossible without it.