Accurate Hydrometer readings
July, 2003 Filed in: Wine making
Hydrometers are calibrated to the specific gravity of water at 60oF. The specific gravity of water at this temperature is 1.000. Temperature can impact the reading on your hydrometer. If you would like to accurately use your hydrometer, insuring it is calibrated, here is an idea.
Keep a pitcher of water close to the primary so it stays at the same temperature as the wine. Any deviation from 1.000 would be due to calibration discrepancy or temperature adjustment and, if it reads high or low, the reading of the wine will be equally high or low. So, for example, if the reading in the pitcher of water is 1.002 you would subtract .002 from the reading you get in the wine; if the reading of the water is .998, you would add .002.
Keep a pitcher of water close to the primary so it stays at the same temperature as the wine. Any deviation from 1.000 would be due to calibration discrepancy or temperature adjustment and, if it reads high or low, the reading of the wine will be equally high or low. So, for example, if the reading in the pitcher of water is 1.002 you would subtract .002 from the reading you get in the wine; if the reading of the water is .998, you would add .002.