What is a Hydrometer?

Learn why you need a hydrometer, what is measures, and how it works.

Why do I need an Hydrometer?

Your hydrometer provides you with accurate specific gravity readings that indicate when certain stages of the wine and beer making processes are complete. Specific gravity (S.G.) is the density of a liquid. In the case of wine and beer making you are measuring the amount of sugar that is in the liquid.

What is Specific Gravity (S.G.)?

The S.G. of plain water is 1.000, the more sugar that is in a liquid the higher the reading. Most wine kits read at about 1.080 at the start of the fermentation process, most beer kits start at about 1.035 S.G. As the fermentation process takes place the sugar is consumed by the yeast and is converted to alcohol and carbon dioxide As a result Beers will typically have a finished S.G. reading of about 1.002-1.006. as there is usually residual (unfermented) sugar left in the beer.Wines will typically have a S.G. of 0.990-0.960.Wines have a lower finished gravity because the higher alcohol content of wine makes the finished gravity less than that of plain water.

How does an Hydrometer Work?

A hydrometer does not have a mercury scale like a thermometer .Your hydrometer is designed to float in the liquid you are measuring the specific gravity of.To take a hydrometer reading, simply float your hydrometer in the wine or beer and take the reading where the hydrometer sticks out of liquid (such as a test jar). Remember to give the hydrometer a spin to dislodge any CO bubbles that may be clinging to the hydrometer. Its easy enough to take a hydrometer reading while the wine is in the primary fermentor, when it is in the carboy however, it is best to remove a sample and take the reading in a test jar. A handy tool for this is called "The Thief".

The Thief will take a sample from your carboy, you can then drop your hydrometer directly into The Thief & take the S.G. reading. The hydrometer is one of the most important and simplest tools for the home wine maker. It lets you know when certain stages of the wine making processes are complete is the easiest way to ensure your wine & beer making trouble free! The last thing to remember is to write your hydrometer readings down somewhere.