The hydrometer is a simple device that is floated in the must or the wine within a test jar. The depth of which the hydrometer sinks gives the measure of the sugar level in the liquid. The hydrometer
measures the specific gravity (density or weight) before fermentation starts and the reading is noted. Readings in the table below gives sugar readings per 4.5 litres (gallon) and the potential
% alcohol to be produced. Whenever the strength is too low, then it is necessary to add more sugar.
Generally, table wines should be between 10% - 12% and dessert wines between 12-14%. As a comparison, beers are normally between 3 - 6% and barley wines can reach 8%.
Summarising, the hydrometer allows you to find out:-
- The amount of sugar naturally occurring initially in the juice or must.
- The amount of sugar to be added to reach a desired final alcohol content.
- The progress of the wine during fermentation.
- A final check when the wine has finished and the alcohol strength attained.
The following table measures alcohol content.