hygrometer calibration how to calibrate hygrometer
How to Calibrate a Hygrometer
A hygrometer is a gage used to estimate the level of humidity inside the humidor, at a pressure less than 1 atm. There are different methods used to calibrate this gage; to know more, read on.
- A hygrometer
- ½ cup table salt
- Nearly ¼ cup water
- Coffee cup
- Large resealable freezer bag
- Put the salt in the coffee cup and add water. Stir for a while, so that the water saturates completely. Though, it won't dissolve entirely, it will produce a wet sand-like consistency.
- Place this mixture in the resealable plastic bag, along with the hygrometer, and seal the bag. Make sure that the mixture is not in direct contact with the hygrometer. Then, carefully place the cup in the resealable plastic bag.
- Keep this bag aside at room temperature for about 8-12 hours. The place should not be windy, away from direct sunlight, and heating or cooling vents. The temperature should be fairly constant.
- After being kept in the bag for 8-12 hours, measure the reading. It is advisable to read it while it is still in the bag, because if the outside air is dry, the reading will immediately drop once the hygrometer is out of the bag.
- The relative humidity in the sealed bag should be 75%. If the reading is anything other than 75%, it should be changed to 75%. For non-adjustable hygrometers, make a note of the reading and then add or subtract from the true reading to get the correct humidity level. For example, if your hygrometer reads 72% then add 3% to it, and to all future readings you take.