To measure the alcohol content with a hydrometer, you will need a test jar and the hydrometer itself. The test jar should be filled with the liquid you want to measure, leaving about 35mm of space from the top. This space is necessary to allow the hydrometer to float freely without touching the sides of the jar.
Once you have filled the test jar with the liquid, simply drop the hydrometer into it. Make sure that the hydrometer is fully submerged in the liquid and not touching the sides of the jar. The hydrometer will float in the liquid, and you will notice that it sinks to a certain level.
To get an accurate measurement, you need to take the reading from the lower of the two levels you see when looking at the side of the test jar. This lower level is the specific gravity (SG) of the liquid. The specific gravity is a measurement of the density of the liquid compared to the density of water.
The hydrometer is calibrated to measure the specific gravity, which can be used to calculate the alcohol content. The specific gravity reading will be higher before fermentation and lower after fermentation. By comparing the specific gravity before and after fermentation, you can determine the alcohol content.
When using a hydrometer, it is important to handle it carefully and avoid touching the sides of the jar or causing any disturbances in the liquid. Even small disturbances can affect the accuracy of the reading.
In my experience as a brewer, using a hydrometer to measure alcohol content is a crucial step in the brewing process. It allows me to track the progress of fermentation and determine when the desired alcohol content has been reached. It also helps me analyze the efficiency of my brewing process and make adjustments if needed.
To summarize the steps to measure alcohol content with a hydrometer:
1. Fill the test jar with the liquid, leaving about 35mm of space from the top.
2. Drop the hydrometer into the liquid, ensuring it is fully submerged and not touching the sides of the jar.
3. Take the reading from the lower of the two levels you see when looking at the side of the test jar.
4. This reading is the specific gravity (SG) of the liquid, which can be used to calculate the alcohol content.
Using a hydrometer is a simple and effective method to measure alcohol content in various liquids, including beer, wine, and spirits. It provides valuable information for brewers and sommeliers to understand and control the alcohol content of their products.