A hydrometer measures specific gravity (S.G.) and is crucial to monitoring the progress of fermentation. It’s very easy to measure, just follow these steps!
1. Clean and sanitize your hydrometer.
2. Put sample of wine into test jar ensuring there is enough for the hydrometer to float freely (see picture 1). You may also place the hydrometer directly into the primary fermenter (see picture 3).
3. Place hydrometer in middle of jar. It may naturally want to stick to the side of the test jar, so give it a gentle tap to encourage it to move towards the middle of the jar. If you’re testing in the primary fermenter, place the hydrometer near the centre and clear away any surrounding bubbles to make it easier to read.
4. With the jar or fermenter on a flat surface try to get your eyes as level as possible with the hydrometer (see picture 2). Note the reading at the bottom of the curve of the liquid surrounding the hydrometer. This curve is called the meniscus and the most accurate reading is given at the bottom, the same as with reading liquid in a measuring cup for baking.
5. Refer to S.G. chart in your instructions to figure out where your wine is in its fermentation process.