Have you ever been SURE your wine is ready to stabilize but your hydrometer tells you it has not finished fermenting?
As fermentation slows, less and less C02 is produced. Eventually, the C02 does not create enough pressure inside the carboy to push through the water in the airlock.
When that happens, the C02 has to go somewhere, so it dissolves into the wine. When wine becomes saturated with C02, you may get a false reading as the saturated gas lifts the hydrometer.
A wine will appear to have finished fermenting when it has been given sufficient time for our region, there is no surface action, and no action in the airlock. The final decision should always be made by specific gravity reading with your hydrometer. But what can you do to test if you feel your hydrometer is lying to you?
How to Use Hydrometer
First gently spin your hydrometer to ensure that there are no bubbles clinging to it and falsely elevating. If that doesn’t help, you could degas prior to stabilizing. While there is always gas in the wine to remove after stabilizing, sometimes there is so much gas that it can affect your readings.