How to read a Hydrometer

Reading the amount of sugar in your wort or must is very easy and can be accomplished with the following steps:

1) Fill the hydrometer jar 2/3 full
2) Place the hydrometer inside the jar with the solution
3) Read the level where the hydrometer floats

First fill your hydrometer with a sample from your wort or must.  The hydrometer jar should contain enough juice for the hydrometer to float.  If there is carbonation still in your solution or if your sample contains foam, try pouring the solution into a glass and then back into the jar.  Repeat this until the foam or carbonation subsides.

Next, carefully place your hydrometer into the jar.  If the hydrometer causes the jar to overflow, pour a bit out.  Let the jar with the hydrometer rest for a minute until the hydrometer stops bobbing.

Move to a position where you can view the hydrometer at eye-level.  The gravity level for potential alcohol is the point where the hydrometer exits the solution.  The curved surface of a liquid in the hydrometer jar, as seen in the image below, is called the meniscus.  The value is read at the bottom of the meniscus.

Make sure that you record the temperature of the solution everytime you take a hydrometer reading.  The reason is that temperature can affect the reading.  If two different readings cannot be taken at the same temperature, make sure you adjust the reading using the scale on your hydrometer.

You can test the accuracy of your hydrometer by taking two readings.  Make sure that your hydrometer reads 1.000 when placed in water.  You should also take a second reading in a solution with a known specific gravity.