Enjoy the beer that you deserve.
What it does :
The hydrometer provides measurements that you, the brewer, need to control the fermentation of your beer.
What it is:
A hydrometer is a simple glass instrument used to measure the specific gravity of liquids.
How it works:
A hydrometer uses the buoyancy of fluids to determine their sugar content. It is typically marked in two scales, the specific gravity scale and the Balling scale. These scales indicate the fermentation potential of the fluid, whether wort or beer. Measurements are taken throughout the beermaking process to check progress.
Hydrometers are used during the cold side of brewing (e.g. fermentation, bottling, and packaging). However, they typically do not come into contact with the fermenting beer as you should withdraw a sample for gravity measurements. Therefore, simply keep it cleaned for use.